Biosynthesis of AAs (mini-test 2) Flashcards
When are AAs synthesized in the body- fed or fasting state?
fed state
How many essential AAs are there for kids compared to adults?
10 essential AAs for kids, 8 for adults (2 are conditional)
this means these AAs need to be obtained from diet
Nonessential AAs can be synthesized from intermediate metabolites or…
essential AAs
All AAs are derived from intermediates of ____________ metabolism
glucose
VITM are 4 AAs that can synthesize SCoA. How many of these AAs can be synthesized within the body and are nonessential?
none of them! All 4 are essential
What AAs can be synthesized from alpha KG?
Glutamate can synthesize what AAs?
-glutamine
-proline
-arginine
PHAGG are 5 AAs that can synthesize….
alpha KG
Phe is essential, but once in the body it can synthesize tyrosine with phenylalanine hydroxylase. What can tyrosine synthesize from here?
fumarate
What AAs are made from OAA?
Asp and Asn
OAA will make Asp with AST and then Asp can convert to Asn
What AAs can be made from pyruvate?
alanine only
G CAST are 5 AAs that can make….
pyruvate
What AAs can be made from 3 phosphoglycerate (glycolysis intermediate)?
-serine
-cystiene
-glycine
3PG can make Ser which then can make either Gly or Cys
What AAs can be made from phenylalanine?
tyrosine
The sulfur group of homocysteine is transferred to serine to make….
cysteine
Is methionine essential or nonessential?
essential
Is cysteine essential or nonessential?
nonessential BUT it will become essential only if theres not enough methionine in the body
What are the 3 aromatic AAs?
1) trp
2) phe
3) tyr
Aromatic rings in aromatic AAs are derived from a common precursor called….
chorismate
The indole ring for trp is synthesized from chorismate and…
phosphoribosyl pyrophosphate (PRPP)
What is PRPP?
phosphoribosyl pyrophosphate (PRPP)
-it is an active form of ribose
-used in synthesizing nucleotides (ATP, GTP, UTP, CTP), histidine, and tryptophan
major function is to create nucleotides!
What are the 2 most common biomolecules derived from AAs?
1) proteins
2) precursors of other nitrogen containing compounds called amines (porphyrins, neurotransmitters, hormones, purines, pyrimidines, coenzymes, etc)
Porphyrin + _____ = heme
Fe
What part of heme binds to oxygen?
Fe
What are some examples of hormones that get synthesized from AAs?
-thyroid hormones
-glucagon
-insulin
Can the body synthesize mature heme?
NO
What are porphyrins?
-cyclic organic compounds that bind metal ions
-they are found primarily on chromoproteins like hemoglobin, cytochromes, and chlorophyll
-the ring structure is assembled mainly from glycine
-most prevalent is heme, which is one ferrous iron coordinated in the center of the ring and it is rapidly synthesized and degraded
decreased heme=
anemia
The ring structure of porphyrins is assembled mainly from what AA?
glycine
glycine + _______ will eventually make the porphyrin ring
SCoA
What disease is caused from defective heme synthesis?
porphyrias
What symptom is caused from defective heme breakdown?
jaundice
note: this is a SYMPTOM not a disorder
What is porphyrias?
-enzyme deficiencies in heme biosynthesis with harmful accumulations of porphyrins or precursors
-genetic or acquired (too much iron, liver diseases, smoking, excessive alcohol use)
symptoms:
-photosensitive skin, pain with light exposure in less then 30 min, can cause permanent skin damage
-GI symptoms
-high BP
-breathing issues
-seizures
-paralysis
-RBCs are vulnerable and can easily burst and cause bruises and bloody urine
tx:
-avoid triggers
-injections of heme to limit the body’s production of porphyrins
-treatment of symptoms
When heme gets broken down it first turns into biliverdin and then….
bilirubin
Which organ will do hemolysis of old RBCs and release hemoglobin?
spleen
Bilirubin is transported in the blood with….
albumin
indirect bilirubin build up will cause a hemolytic crisis and physiological jaundice in newborns. What is this?
-high levels of hemolysis to break down RBCs
-bilirubin glucuronyl transferase is low at birth
-treated with blue light
-hyperbilirubinemia is neurotoxic (kernicterus)
Unconjugated/ indirect bilirubin will bind with 2 UDP glucuronate to form bilirubin diglucuronide (this is conjugated/direct bilirubin). What enzyme does this?
bilirubin glucuronyl transferase
direct or indirect bilirubin can cause _________ damage and depends on the degree of damage
liver
Direct bilirubin causes bile duct obstruction which results in….
clay color stool
What is jaundice?
-yellowing of skin, sclerae, and nail beds
-due to hyperbilirubinemia (accumulation of bilirubin direct or indirect)
What are the major causes of jaundice?
usually due to liver or gallbladder dysfunction
What is the main source of bilirubin?
heme degradation
Creatine is made from what 2 AAs?
arginine and glycine
Muscles contain creatine that is phosphorylated to creatine phosphate by….
creatine kinase (CK)
(creatine kinase uses ATP as a phosphate donor. Elevated creatine kinase isoenzyme in the blood indicates the location of tissue damage)
Skeletal muscle expresses which CK enzyme?
CK- MM
Heart muscle expresses which CK enzyme?
CK MM (same as skeletal m.)
but the unique one is- CK-MB
The brain expresses which CK enzyme?
CK-BB
Creatine phosphate is a reserve of phosphates for ATP. it provides a rapid response to muscle ATP demands for the first few minutes of intense muscle use by….
substrate level phosphorylation
Creatine is degraded by spontaneous cyclization to ________________ that is removed by the kidney and excreted in urine.
creatinine
note: a rise in blood creatinine may indication kidney damage
What are the 2 kidney markers in blood we learned so far?
-increased BUN levels
-increased creatinine
note: “normal” body builders have high creatinine but normal BUN, but if both BUN and creatinine is high then theres a problem
What do increased CK-BB levels mean in the blood?
stroke
What do increased CK-MB levels mean in the blood?
heart attack
CK BB, CK MB, and CK MM are ____________
isozymes
Carnitine shuttles _____ across the mitochondrial inner membrane
FAs
What AA is carnitine derived from?
lysine
Which AA makes thyroid hormones (thyroxine), melanin, catecholamines (dopamine, epi, and NE)?
tyrosine
which AA makes serotinin, NAD and NADP (niacin)?
tryptophan
Which AA makes NO and urea?
arginine
Which AA makes GABA?
glutamate
Which AA makes histamine?
histidine
