Exam 5 Flashcards
1
Q
intermediates in synthesis are llinked to -SH groups of ?
A
acyl carrier proteins (as opposed to SH groups of CoA)
2
Q
synthesis occurs where?
A
cytosol
3
Q
breakdown occurs where ?
A
mitochondria
4
Q
activation of acetate units for FA synthesis
A
know mechanism
5
Q
primary precursor to fatty acids
A
acetyl-CoA and NADPH
6
Q
citrate lyase
A
citrate > acetyl-CoA + OAA
7
Q
malate dehydrogenase
A
OAA to malate
8
Q
citrate-malate-pyruvate shuttle
A
OAA made in matrix, converted to citrate for cytolsol entry. converted to malate or pyruvate for reentry into matrix
9
Q
primary precursors to acetyl-CoA
A
citrate and amino acids
10
Q
how are fatty acids brought into matrix
A
fatty acid > fatty acylCoA > fatty acyl-carnitine > entry > acetyl-CoA
11
Q
malate dehydrogenase
A
malate > OAA
12
Q
fats synthesized when ? (4)
A
high glucose, high atp, low amp, low fatty acyl CoA
13
Q
glycolysis intermediate used to make triglycerol backbone
A
DHAP. converted to glycerol 3 phophate
14
Q
pyruvate carboxylase
A
pyruvate to OAA
15
Q
pyruvate dehdrogenase
A
pyruvate to acetyl CoA
16
Q
acetyl CoA carboxylase
A
acetyl CoA to malonyl CoA
17
Q
fatty acid synthase
A
malonyl CoA > palmitate
18
Q
citrate lyase
A
citrate > OAA + acetyl CoA. requires ATP, induced by insulin
19
Q
how can glucose give rise to acetyl CoA
A
glucose > pyruvate > into matrix > OAA + acetly CoA > citrate > into cytosol > OAA + acetyl CoA
20
Q
citrate in cytosol produces two key intermediates
A
acetyl CoA and regenerates pyruvate
21
Q
malic enzyme
A
malate to pyruvate
22
Q
Acetyl CoA carboxylase
A
acetyl CoA +CO2 to malonyl CoA. uses ATP and biotin. RATE limiting. Activated by citrate
23
Q
effect of phosphorylation on acetyl CoA carboxylase
A
active when dephosphorylated
24
Q
fatty acid synthase net reaction
A
1 acetyl coa + 7 malonyl coa + 14 NADPH > 1 palmitate
25
synthesis of palmitate onFA synthase complex
know mechanism
26
malonyl CoA regulation of FA synthesis
blocks carnitine acetyltransferase
27
desaturase
adds double bond to fatty acid
28
transfers choline to a diacylglycerol
cdp-choline
29
phospholipase 1 and 2
cleaves acyl chain at 1 and 2 positions of glycerophospholipids
30
cholesterol is a precursor to ?
bile acids, hormones, and vitD
31
HMG CoA reductase
catalyzes methyl glutaryl CoA to mevalonic acid
32
eicosanoid
20 carbons, formed from arachidonic acid.
33
cyclo-oxygenases catalyze
arachidonic acid to prostaglandins or thromboxanes
34
backbone of all sphingolipids
ceramide
35
precursors for ceramide synthesis
palmitoyl-CoA and serine
36
intermediates in FA synthesis linked to ?. In breakdown linked to ?
intermediates in FA synthesis linked to -SH of acyl carrier proteins. In breakdown linked to -SH of CoA
37
FA synthesis occurs in ?. FA breakdown occurs in ?
FA synthesis occurs in cytosol. FA breakdown occurs in mitochondria
38
FA biosynthesis uses NADPH or NADH
NADPH/NADP+
39
FA breakdown uses NADPH or NADH
NADH/NAD+
40
fomration of ? activates acetate units for FA synthesis
malonyl-CoA
41
in humans, synth of FA from glucose occurs mainly in ?
liver
42
conditions where fat is synthesized
glucose is high, atp is high, amp is low, fatty acyl coa is low
43
citrate lyase reaction catalyzed
citrate to acetyl CoA and OAA. uses ATP, induced by insulin
44
catalyzes citrate to acetyl CoA and OAA
citrate lyase. uses ATP, induced by insulin
45
OAA to malate to pyruvate (2 enzymes)
malate dehydrogenase (uses NADH) followed by malic enzyme (makes NADPH)
46
catalyzes acetyl CoA to malonyl CoA
acetyl CoA carboxylase (+ biotin), uses ATP and CO2
47
acetyl CoA carboxylase allosterically acitvated by ?
citrate
48
rate limiting enzyme of FA synthesis
acetyl coa carboxylase
49
effect of insulin on acetyl CoA carboxylase
insulin activates phosphatase. dephosphorylates to activate acetyl CoA carboxylase
50
fatty acid synthase structure
homo dimer with all 7 enzyme activities on each subunit. cotains acyl carrier protein (ACP). contains phosphopantetheine residue
51
three components required for fatty acid synthase to male 1 palmitate
1 acetyl-CoA. 7 malonyl-CoA + 14 NADPH
52
phosphopentetheinyl residue significance in FA synthase
derived from panthethenic acid. covalently linked to serine of ACP. sulfhydryl reactions with malonyl CoA to form thioester
53
FA elongation beyond 16 C and desaturation occurs here?
in the ER. desatration not possible in this manner beyond Delta 9
54
arachidonic acid is synthesized from ? in eukaryotes
linoleic (both termed omega 6's)
55
essential fatty acids
linoleic and linolenic
56
precursor to DHA and EPA
alpha linolenic (termed omega 3s)
57
what do omega 6 and omega 3 mean
have 6 or 3 carbons from last double bond
58
blocks carnitine acyltransferase to inhibit beta oxidation
malonyl coA
59
inhibits acetyl coa carboxylase
fatty acyl CoAs
60
how is ACC (acetyl coa carboxylase regulated)
activated by glucagon, inhibited by insulin
61
glycerophospholipids are major component in cell membranes and are also found in ?
blood lipoproteins, bile, and lung surfactant
62
sphingolipids are major component in cell membranes and also have a role in ?
cell signalling and formation of myelin sheath
63
3 types of glycerolipids
triacylglycerols, glycerophospholids, ether glycerolipids
64
2 types of sphingolipids
sphingophospholipids and glycolipids
65
function of PIP2 (phosphatidyl inositol bisphosphate)
signalling
66
where is cardiolipin found (exclusively)
mitochondrial membranes
67
degrade glycerophospholipids (2)
phospholipases or lysosomes
68
phospholipases that cut sn1 and sn2 position of glycerophospholipids
phospholipase A1 and A2 respectively
69
phospholipases that cut phospho-head group of glycerophospholipids
phospholipase C
70
phospholipases that cut head group of glycerophospholipids (leaves phosphate attached to glycerol)
phospholipase D
71
major storage form for energy utilization
triglycerides
72
triglycerides stores in ?
adipose
73
two fates of fat
storage or oxidation (make atp)
74
gallbladder fncn
release bile salts
75
thermodynamically unfavorable for fat to go through lumen of gut. driven by ?
thermodynamics
76
biles salts made in ?. secreted by ?
liver. gallbladder
77
precursor of bile
cholesterol
78
emulsifies (chops up) fat
bile
79
% bile excreted in feces
5%
80
once fat is chopped by bile. what do lipases do ?
generate monoacylglycerols and diacylglycerols (cut at C1 and C3)
81
chylomicrons
after crossing intestinal mucosa, acyl chains and monoglycerides reform with other lipids for transport
82
why does bile inhibit lipases
prevents lipases from functioning until bile has completed function
83
colipase function
binds to fat and lipase to release bile salt
84
pancreas produces these enzymes that break down fat
lipases, esterases, phospholipase A2
85
chylomicrons generally transported to ? (2)
adipose for storage or muscle for use
86
lipoprotein lipase function
breakdown fats of chylomicrons for entry into adipose or muscle
87
where are TGs made independent of digestion
liver and adipose. different metabolic pathways!!!
88
proteins for chylomicrons made in ?
rough ER
89
function of proteins in chylomicrons
direct to location
90
major apoprotein of chylomicrons
B-48
91
albumin function
picks up fat when chylomicrons are broken down. fats are not soluble in blood alone. transfers to adipose to muscle
92
most abundant protein in blood stream
albumin (40mg/ml)
93
three functions of albumin
80% of osmotic pressure of blood plasma, macromolecular anion with buffering capacity, transport of hydrophobic substances
94
free FA conc in blood
0.1 nM
95
concentration of FA bound to albumin
1 mM
96
fasting state driven by ?
glucagon
97
glucagon liberation of adipose TAG for energy
activates adenylyl cyclase that makes cAMP, activated protein kinase, activates TAG lipase, breaks down TAG to MAG. albumin picks up free FA
98
insulin blocking liberation of adipose TAG for energy
activates phosphatase that inactivates (dephosphorylates) TAG lipase
99
ATGL
adipocyte TAG lipase
100
HSL
hormone sensitive lipase
101
ATGL and HSL function
break down TAG in adipose. under hormonal regulation : activated by glucagon via PKA. both rate limiting.
102
length of most fats consumed
medium (6-12) and long (12-20)
103
transport of FA for oxidation
binds albumin, crosses plasma membrane, converted to fatty acyl CoA for entry into outer mito matrix.... continued
104
acyl CoA synthetase
activates carboxyl group of FA. uses ATP!!
105
three fates of fatty acyl CoA
energy, storage, attached to membrane lipids
106
cpt 1
removes CoA, attaches carnitine. allows transfer into mitochondrial matrix
107
transfers acyl carnitine to inner mito matrix
translocase
108
whats happening in beta oxidation
shortening of FA by 2 carbons. dehydrogenase to double bond. addition of water across double bond. dehydrogenase to ketone. cleavage.
109
ATP/carbon from fatty acids
8
110
atp/carbon of glucose
6.3
111
higher ATP yield per carbon. fat vs glucose
fat
112
3 major mech of inhibting oxidation
high atp, high reducing, making fat (generation of malonyl CoA)
113
why is medium chain oxidation unique
primarily goes to liver. more water soluble. enter blood directly
114
oxidation of odd chan FAs
generates propionyl CoA. converted to succinyl CoA and feeds into TCA cycle
115
specificity in beta oxidation
first dehydrogenase is sepcific for FA length
116
peroxisomes handle which type of fatty acids
very long chain
117
primary site of cholesterol synthesis
liver
118
synthesis of mevalonate from acetyl-CoA
1) thiolase rxn 2) HMG-CoA synthase 3) HMG-CoA reductase to mevalonate
119
conversion of mevalonate to squalene driven by?
Atp and PPi hydrolysis, and decarboxylation
120
twenty enzymes required to convert lanosterol to cholesterol are where?
ER assoicated
121
statins increase/decrease serum cholesterol. example of statin?
decrease. lipitor targets HmG-CoA reductase
122
Eicosanoids
prostaglandins and thromboxanes. "local" hormones. major role in inflammatory response
123
most common precursor of eicosanoids
arachidonic acid
124
arachidonic acid is synthesized from what?
linoleate
125
arachidonic acid released from lipid bilayer by?
phospholipase A2 or C
126
where do NSAIDs act
cyclooxygenase
127
action of ceramides depends on ?
carbon chain length
128
other FA oxidative pathways
peroxisomal, alpha oxidation, omega oxidation
129
peroxisomal oxidation
not as efficient as beta. requires FAD dependent acyl-CoA for very long chain
130
alpha oxidation
for branched chains
131
ketone bodies
special source of fuel for brain, heart and muscle. converted to acetoacetate and hydroxybutarate in target organ
132
makes but does not use ketone bodies
liver
133
predominant ketone body
hydroxybutyrate (more abundant that acetoacetate)
134
oxidation of ketone bodies (key points)
made in liver. dumped into target tissue (not liver). Converted to acetyl CoA in mitochondria.
135
Regulation of ketone body oxidation
reducing equivalent and ATP turns off. acetyl CoA is checkpoint. depends on TCA cycle enzymes
136
lipoproteins
proteins carrying lipids. polar monolayer surface. neutral lipid core. ex. HDP, VLDL, chylomicrons.
137
HDL and VLDL assembled where?
ER of liver cells
138
chylomicrons formed where ?
intestines
139
LDL assembled where
not made directly. made from VLDL
140
Apo
describes protein that is lipid-free
141
function of apoproteins
structure. enzyme activation for lipoprotein metabolism. serve as ligands
142
chylomicrons composition and density
low density. high in TAG. low protein. low cholesterol
143
what makes a dense lipoprotein
more protein, less lipid
144
significance of lipoprotein particle size
dictate function (transport abilities), contribute to obstruction of arteries
145
apoCII
activates lipoprotein lipase to release TAG.
146
apoE
after loss of core TAG, drives chylomicron back to liver
147
first FA made in liver
palmitic
148
nascent VLDL contains ?
apoB100
149
in circulation, HDL donates ? and ? to from mature vLDL
apoCII and apoE
150
HTGL
lipase responsive to IDL metabolism. removes TAG from IDL to form LDL
151
VLDL remnants
particles remaining post hydrolyis. half taken up by liver, rest forms IDL
152
three ways to make HDL
synth by liver. budding of apoproteins. from free apoA1
153
transfer of lipids to nascent HDL does not require ?
enzymatic activity
154
reverse cholesterol transport
Protein ABCA1 uses ATP hydrolysis to move cholester to outer leaflet. HDL accepts cholesterol and modifies with LCAT to retain it.
155
why is cholesterol modified by LCAT
to prevent being picked up by other particles
156
CETP exchange pathway. purpose?
cetp transfers cholesterol esters from HDL to VLDL in exchange for TAG. don't know why it happens.
157
atherosclerosis
inflammatory disease driven by oxidized LDL
158
scavenger receptors
bind oxidized LDL. leads to foam cells.
159
cysteine is made from
methionine
160
tyrosine is made from
phenylalanine
161
initial phase of protein digestion
gastric phase. digestion by stomach protease.
162
2 mechanisms of generating pepsin
pepsinogen undergoes conformational change and cleaves self.
163
major protease in stomach
pepsin
164
second phase of protein digestion
pancreatic phase. digestion by pancreatic enzymes in duodenum.
165
activates chymotrypsinogen and proelastase
trypsin
166
AA cleaved by trypsin
basic
167
AA cleaved by chymotrypsin
aromatic
168
outcome of pancreatic phase
AAs and small peptides
169
third phase of protein digestion
intestinal phase. digestion of peptides by intestinal surface enzymes
170
how are AA absorbed in lumen of intestine
sodium or proton dependent transporter
171
two main proteolytic degradation of damaged proteins
ubiquitin dependent and lysosomal degradation
172
ubiquitin proteasome proteolytic pathway
proteasome is cyllinder with regulatory subunits that regulate entry.
173
lysosomal degradation
protein delivered by endocytosis, autophagy (obsolete organelles) or phagocytosis (consume bacterial protein)
174
aminotransferases
remove alpha amine from AA and donate to alpha keto acid. used in degradation and synthesis
175
coenzyme of aminotransferases
PLP
176
predominant aa/alpha keto acid pair
glutamate/alpha keto glutarate
177
three common aminotransferases
alanine, aspartate, glutamate
178
versatility of PLP
forms schiff base. bond broken depends on bound enzyme (stereoelectronic control). bound to aminotransferase, breaks C-H bond
179
vitamin B6 deficiency
identified by xanthurenic acid.
180
highest circulating aa in blood
alanine and glutamine
181
NH4+ vs NH3 abundance in blood
NH4+ more abundant
182
ammonia + alpha ketoglutarate
glutarate
183
ammonia + glutamate
glutamine
184
glutamate dehydrogenase. mitochondria vs liver.
converts between alpha ketoglutarate and glutamate. In liver favors glutamate to pick up free ammonia.
185
glutaminase
glutamine to glutamate (irreversible)
186
fates of ceramide
sphingomyelin, shingosine (then S1P), glucosylceramide
187
daunorubicin activates these enyzymes (2)
ceramide synthase and sphingomyelinase
188
ceramidase
ceramide to shingosine
189
drugs that synergize for ceramide production in cancer cells
4-HPR and tamoxifen
190
tamoxifen effect
targets glucosylceramide synthase. blocks glycosylation of ceramide
191
4-HPR effect
targets serine palmitoyl transferase. generates sphinganine and in turn, ceramide
192
3 avenues for enhancing intracellular ceramides
de novo, shingomyelinase, exogenous
193
ceramide signalling pathways most commonly pass through this organelle
mitochondria
194
effect of ceramide on cancer cells
apoptosis, autophagy, cell cycle arrest
195
S1P function
enhances tumor growth. inhibit SK to rpevent
196
two types of autophagy
survival and lethal
197
htgl
hepatic triglyceride lipase. Remove TG from IDLs to form LDL
198
ldl receptor
recognizes apoB100 and apoE. binds LDL as well as VLDL, IDL, and chylomicrons
199
where does digestion and absorption of proteins occur
lumen of GI tract
200
proteins are hydrolyzed by ____
peptidases
201
peptidases
secreted as zymogens (inactive form). endopeptidases (internal cleavage) and exopeptidases (carboxy and aminopeptidase)
202
kwashiorkor
condition resulting from inadequate protein intake. fatigue, large belly, growth failure.
203
pepsin
major protease in stomach. active at low pH. cleaves peptide bond
204
gastric juice
pH < 2 from HCl. kills microorganisms, denatures protein.
205
gastrin
hormone stimulated by food in stomache. stiumlates mucosa to lower pH. stimulates chief cells to release pepsinogen
206
chyme
acidic contents of stomach
207
function of chief cells
release pepsinogen
208
secreted by intestinal endocrine cells in 2nd phase of protein digestion
secretin and CCK
209
acute pancreatitis
zymogens activated inside pancreas cells
210
pancreatic enzymes activated during pancreatic phase of protein digiestion
trypsin, chymotrypsin, elastase
211
what occurs of luminal surface of intestinal epithelial cells during intestinal phase of protein digestion
cleavage of dipeptides and oligopeptides into free AA, dipeptides and tripeptides by peptidases (endo, di, and aminopeptidases)
212
what occurs in intestinal epithelial cells during intestinal phase of protein digestion
absorption of AA via Na and H dependent transport. Na gradient maintained high on outside by active transport exchange with K
213
type of transport that carrier AA from epithelial cell into blood
facilitated transport
214
hartnup disease
defective neutral AA transport into epithelial cells
215
cystine tranport
cysteine homodimer transported by basic AA transporter. transporter defect leads to kidney stones
216
4 steps of ubiquitin-proteasome proteolytic pathway
ubiquitin added to epsilon-amino group via 3 ATP requiring enzymes. regulatory subunits of proteasome recognize, unfold and transport to core. peptides released and ubiquitin regenerated. peptides degraded to AA
217
proteins commonly degraded via lysosomes
extracellular or long lived protein
218
from where is nitrogen obtained
dietary and body proteins
219
dietary proteins are digested in ___
gut
220
AA are transported to the liver via the ____
hepatic portal vein
221
fate of excess AA
converted to glucose or TAGs
222
fate of AA that pass through liver
go to other tissues and converted to protein
223
In fasting state, muscle protein is digested to ___
AAs
224
Fate of AA acids digested from muscle protein in fasting state
some released into blood. others partially oxidized to alanine and glutamine and enter blood
225
fate of glutamine relased into blood from muscle during fasting state
goes to either kidney or gut where it is converted to alanine (to blood) and ammonia (into urine)
226
fate of AA nitrogen in liver during fasting
converted to urea
227
fate off AA backbones in liver during fasting
converted to glucose and ketone bodies
228
function of aminotransferases
remove alpha amino group from amino acid and transfer to alpha ketoacid. Reversible.
229
coenzyme of aminotransferases
PLP (pyridoxal phosphate)
230
predominant AA/alphaketoacid pair
glutamate/alpha-ketoglutartate
231
first partial reaction of aminotransferase
alpha amino group + E-PLP goes to alpha ketoacid + E-PMP
232
second partial reaciton of aminotransferase
alpha ketoacid + E-PMP goes to amino acid + E-PLP
233
alanine + alpha ketoglutarate goes to ____ + ____in liver
pyruvate + glutamate
234
glutamate + OAA goes to ___ + ___ in liver
aspartate + alpha-ketoglutarate
235
levels are monitored to measure liver damage
AST and ALT
236
functional group of PLP
aldehyde. forms shiff base with AA substrates. linked to lysine of enzyme when substrate is absent
237
symptoms of B6 deficiency
dermatitis, microcytic
238
ammonia serum levels and pKa
30 to 60 uM. pKa=9.3
239
ammonia fixed into ___ to produce glutamate
alpha ketoglutarate
240
ammonia fixed into ____ to produce glutamine
glutamate
241
region of liver where ammonia is incorporated into glutamate or glutamine
perivenous region
242
glutaminase function
converts glutamine to glutamate in mitochondra of kidney and liver. releases ammonia!
243
glutamine synthetase net reaction
glutamate + ammonia + ATP goes to glutamine + ADP
244
catalyzes glutamate + ammonia + ATP to glutamine + ADP
glutamine synthetase (occurs in perivenous region of liver)
245
converts glutamine to glutamate in mitochondra of kidney and liver. releases ammonia!
glutaminase
246
glutamate dehydrogenase function in mitochondria
produce alpha ketoglutarate and release ammonia from glutamate
247
glucose-alanine cycle
glucose to pyruvate to alanine in muscle. Alanine to pyruvate to glucose in liver.
248
nitrogen atom of most amino acids are transferred to ___
alpha ketoglutarate
249
urea made in urea cycle using ___ and ___
ammonia and aspartate
250
aspartate transaminase reaction
glutamate + OAA makes aspartate and alpha ketoglutarate
251
glutamate + OAA makes aspartate and alpha ketoglutarate
aspartate transaminase reaction
252
____ + ____ makes aspartate and alpha ketoglutarate using aspartate transaminase
glutamate + OAA
253
glutamate dehydrogenase produces ? and ammonia from glutamate
alpha ketoglutarate
254
deamination of purines to produce ammonia occurs where
muscle and BRAIN
255
bacterial urease
releases ammonia from urea
256
sources of urea
AA degradation in gut. urease. glutamate dehydrogenase. deamidation of gln and asn (intestine). deamination of ser, thr, gly, met, and his. deamination of purines.
257
complete urea cycle is significant only where?
liver
258
five enzymes of urea cycle
carbamoyl phosphate synthetase. ornithine transcarbamoylase. argininosuccinate synthetase. argininosuccinate lyase. arginase.
259
carbamoyl phosphate synthetase 1 reaction
HCo3 + 2 ATP + NH4 goes to carbamoyl phosphate + 2 ADP + P. occurs in mitochondria.
260
ornithine transcarbamoylase reaction
ornithine from cytosol + carbamoyl phosphate goes to citrulline in mitochonria which moves to cytosol
261
ornithine from cytosol + carbamoyl phosphate goes to citrulline in mitochonria which moves to cytosol. which enzyme?
ornithine transcarbamoylase
262
HCo3 + 2 ATP + NH4 goes to carbamoyl phosphate + 2 ADP + P. occurs in mitochondria. which enzyme?
carbamoyl phosphate synthetase 1
263
argininosuccinate synthetase reaction
citrulline + aspartate + ATP goes to argininosuccinate + AMP
264
citrulline + aspartate + ATP goes to argininosuccinate + AMP. Which enzyme?
argininosuccinate synthetase
265
argininosuccinate lyase reaction
argininosuccinate goes to arginine + fumarate (to TCA or regenerate aspartate)
266
argininosuccinate goes to arginine + fumarate (to TCA or regenerate aspartate). which enzyme
argininosuccinate lyase
267
intermidates between fumarate to aspartate
fumarate to malate to OAA. OAA + glutamate make aspartate
268
how does fumarate enter the TCA cycle
converted to malate which enters mitochondria
269
arginase reaction
arginine + water goes to ornithine + urea
270
amount of urea excreted by human
10 kg/year
271
allosteric regulator of carbamoyl phosphate synthetase
N-acetylglutamate (NAG) activates
272
n-acetylglutamate synthetase reaction
glutamate + acetyl CoA goes to N-acetylglutamate (NAG)
273
activates N-acetylglutamate synthetase
arginine
274
glutamate + acetyl CoA goes to N-acetylglutamate (NAG). which enzyme?
NAG synthetase
275
alanine aminotransferase reaction
alanine + alpha-ketoglutarate goes to pyruvate + glutamate
276
alanine + alpha-ketoglutarate goes to pyruvate + glutamate. which enzyme
alanine aminotransferase
277
alanine from muscle converted to ___ and __ in fasting state
urea and glucose
278
hyperammonemia. Cause?
elevated ammonia in blood. low or absent urea cycle enzymes.
279
elevated ammonia in blood. cause?
hyperammonemia. low or absent urea cycle enzymes.
280
dietary supplements to increase urea production
arginine and citrulline
281
treat urea cycle defects by increasing or decreasing protein intake?
decreasing
282
treat urea cycle defects by increasing or decreasing alpha-keto acid analogs intake?
increasing
283
levulose function
reduces ammonia by acidifying colon
284
ornithine transcarbamoyltransferase deficiency
accumulation of carbamoyl phosphate. orotic acid exreted in urine via CPS2. develop hyperammonemia in severe cases
285
neurotoxicity associated with high levels of ammonia
high ammonia drives glutamine synthetase (depletes glutamate). low glutamate drives glutamate dehydrogenase (depletes OAA, slows TCA)
286
ketogenic
amino acid catabolic intermediate that can be converted into ketone bodies and fatty acids. Acetyl CoA or acetoacetate.
287
glucogenic
amino acid catabolic intermediates that results in the net synthesis of glucose
288
glycolytic intermediate that gives rise to gly, ser, and cys
phosphoglycerate
289
phosphogylcerate gives rise to these nonessential AA
gly, ser, cys
290
glycolytic intermediate that gives rise to alanine
pyruvate
291
pyruvate gives rise to these nonessential AA
alanine
292
glycolytic intermediate that gives rise to Asn and Asp
OAA
293
OAA gives rise to these nonessential AA
Asn and Asp
294
glycolytic intermediate that gives rise to glu, gln, pro, arg
alpha ketoglutarate
295
alpha ketoglutarate gives rise to these nonessential AA
glu, gly, pro, arg
296
AAs that converge on pyruvate
Thr, Gly, Trp, Ala, Ser, Cys
297
Thr, Gly, Trp, Ala, Ser, Cys converge on this intermediate for entry into TCA
pyruvate
298
AAs that converge on OAA
Asp, Asn
299
AAs that converge on fumarate
Asp, Tyr, Phe
300
Asp, Tyr, Phe converge on this TCA intermediate
Fumarate
301
AAs that converge in Succinyl-CoA via Propionyl-CoA
Val, Thr, Iso, Met
302
Val, Thr, Iso and Met converge on this TCA intermediate
Succinyl-CoA via Propionyl CoA
303
AAs that converge on alpha ketoglutarate
Arg, His, Glu, Pro, Gln
304
Arg, His, Glu, Pro and Gln
converge on this TCA intermediate
305
Acetyl CoA + Acetoacetyl CoA
HMG CoA
306
AA converted to HMG CoA directly
Leucine
307
AA converted to Acetoacetate directly
Phe, Tyr
308
AA converted to Acetyl CoA directly
Thr, Lys, Iso, Trp
309
HMG CoA converted to this ketone body
acetoacetate
310
essential ketogenic AA
leucine and lysine
311
nonessential glucogenic and ketogenic AA
Tyr
312
essential glucogenic and ketogenic AA
Iso, Thr, Phe, Trp
313
essential glucogenic AA
His, Met, val
314
Essential AA
His, Met. Val, Iso, Thr, Phe, Trp, Leu, Lys. PVT TIM HALL
315
biotin function
transfers CO2
316
Tetrahydrofolate (FH4) function
transfers one carbon unit less oxidized than CO2
317
transfers one carbon unit less oxidized than CO2 (3)
tetrahydrofolate, B12, SAM
318
1-carbon pool
pool of 1-carbon groups attached to tetrahydrofolate (FH4)
319
conversion of folate to dihydrofolate to tetrahydrofolate
dihydrofolate reductase. Uses 2 NADPH
320
methotrexate
analog of dihydrofolate that blocks tetrahydrofolate production
321
analog of dihydrofolate that blocks tetrahydrofolate production
methotrexate
322
sources of 1-carbon units for 1-carbon pool
serine, glycine, his, trp
323
groups attached to FH4
formyl, methylene, methyl
324
B12 transfers metyl group to homocysteine forming ?
methionine
325
SAM is produced from ___ and ATP
methionine
326
SAM transfers methyl groups to form ?
creatine, phsophatidylcholine, epinephrine, melatonin
327
relationship between FH4, B12, and SAM
methyl group attached to FH4
328
reactions that require B12
conversion of homocysteine to methionine. methylmalonyl CoA to succinyl CoA
329
conversion from propionyl coa to succinyl coa
biotin converts to methyl malonyl coa, B12 converts to succinyl coa
330
enazymes required for conversion of branched chain AA to glucogenic or ketogenic intermediates
PLP dependent branched chain aminotransferase. branched chain alpha keto acid dehydrogenase
331
BCAAs catabolised by almost all tissues
Val, Iso, Leu
332
maple syrup urine disease
caused by disruption of BCAA catabolism. disrupted alpha keto acid dehydrogenase
333
required to convert phenylalanine to tyrose
phenylalanine hydroxylase and BH4
334
citrate lyase reaction
citrate + CoASH + ATP to OAA + AcylCoA
335
acetyl CoA carboxylase reaction
acetyl CoA + CO2 (via biotin) + ATP to malonyl CoA
336
acetyl CoA carboxylase allosteric regulation
activated by insulin (via phosphatase), activated by citrate, inhibited by palmitoyl CoA
337
precursors to IMP
glutamine + PRPP
338
precursors to PRPP
ribose 5-phosphate + ATP
339
ribose 5-phosphate + ATP
PRPP
340
committed step in purine synthesis
Gln:PRPP amidotransferase. rate limited by PRPP availability
341
purine base backbone comes from ?
glycine
342
puirne nitrogens come from ___ and __
glutamine and aspartate
343
purine carbons come from ? and ?
FH4 and CO2
344
What is the source of the ribose in the nucleotides
ribose 1 phosphate
345
What is the role of folic acid in purine nucleotide synthesis
precursor to tetrahydrofolate. attaches C 2 and 8
346
what is the branch point in purine synthesis
IMP
347
major regulatory site of purine synthesis
PRPP synthetase inhibited by GDP and ADP
348
glutamine phophoribosyl amidotransferase regulation
inhibited by GDP and ADP
349
IMP branch site regulation
feedback inhibited by GMP or AMP
350
importance of salvage pathway
purine synth is expensive (ATP)
351
purine salvage enzyme
HGPRT
352
HGPRT rxn catalyzed
base + PRPP to nucleoside-5-phosphate
353
products of de novo purine synthesis
AMP and GMP
354
How do the salvage pathways influence the de novo synthesis of purine nucleotide?
??
355
How are purine nucleotides degraded?
broken down to xanthine, then to uric acid for urine excretion
356
What is the role of xanthine oxidase?
converts xanthine to uric acid
357
coverts xanthine to uric acid
xanthine oxidase
358
What are the medical problems associated with defects in adenosine deaminase?
SCIDS. can't covert AMP to IMP. dATP inhibition of ribonucleotide reductase impedes DNA synthesis
359
What are the sources of carbons and nitrogens for the pyrimidine ring?
backbone from aspartate, nirtogen from glutamine, carbon from CO2
360
What is the primary regulated step in pyrimidine nucleotide synthesis?
CPS-II
361
CPS-II reaction in pyrimidine synthesis
glutamine + CO2 + 2 ATP goes to carbamoyl phosphate
362
CPS-II regulation
inhibited by UTP. activated by PRPP. activated by low pyrimidine
363
carbamoyl phosphate production in pyrimidine synthesis vs urea cycle
??
