biochem Flashcards
glycolysis production phase
G3P is ox by G3P dehydrogenase to 1,3 BPG
then PEP to pyruvate using #pyruvate kinase
** fructose 1,6 bisphosphate upregulates this, downregulated by ATP
- this one is irreversible
- made 2 ATP and NADH per pyruvate
G6P fates
- glycolysis (glucagon), PPP or glycogenesis (insulin)
- can only be undone to glucose by liver and kidneys
fates of pyruvate
- converted into acetyl coa by #pyruvate dehydrogenase
- oxaloacetate by pyruvate carboxylase
- lactate using lactate dehydrogenase
PPP irreversible ox phase (RLS?)
- makes 2 NADH ribulose 5 P
- G6P is turned into 6 phosphogluconolactone using glucose 6 P dehydrogenase RLS!!
- then 6 phosphogluconate makes ribulose 5 p using 6 phosphogluconate dehydrogenase
PPP non ox phase
- ribose 5 P makes fructose 6 p and G3P
- isomerase makes ribulose 5 p to ribose ( makes DNA)
- epimerase makes xyulose from ribulose
- transketolase transfers 2C from xyulose to ribose making sedahepulose and G3P
- transaldolase removes 3 C from sedaheptulose to make erythrose 4 P adding the last carbons to G3P making fructose 6 P
- if xs xyulose then transketolase transfers 3c from xyulose to erythrose making G3P and fructose 6 phosphate
– uses 3 ribulose!!!
gluconeogenesis
- *pyruvate in mito by pyruvate carboxylase turns to oxalo
- *then #phophoenol pyruvate carboxykinase makes PEP
- G3P made then turned to fructose 1,6 bisphosphate
- turns to fructose 6 P using fructose 1,6 bisphosphatase RLS!!!!
- limited by inuslin and on by glucagon
- then make gluc 6 phosphate to be turned to gluc in liver ER by phosphatase
**oxalo is diverted to form energy!
malate shuttle
transports oxalo across mito to cytosol using malate dehydrogenase in gluconeo
krebs
- # pyruvate dehydrogenase turns pyruvate to acetyl coa in mito
- *citrate synthetase adds it to oxalo (- reg by atp)
- RLS: isocitrate made then turns to a keto glu using isocitrate dehydrogenase (- by ATP, NADH, + by ca)
- *a keto glu turns to succinyl coa by a keto glu dehydrogenase (- by nadh, succinyl coa and atp)
- succinyl coa to succinate = GTP using succinate thiokinase
- succinate makes fumerate using succinate dehydrogenase (FADH!!!)
- malate to oxalo by malate dehydrogenase
**energy made is through substrate level phos
atp synthase structure
- f1 faces the matrix (all the a,b units)
- f0 faces intermem space with all the c1s
- upreg by adp leading to more ox consumption leading to more stim of TCA to make NADH!
anaerobic conditions
- make 2 atp and 2 lactic acid
chylomicrons
- only transport dietary fat
- not associate with fasting state
- structure is monophopholipid layer, cholesterol and TG core
- have apo b48 made in INTESTINE and allows secretion from SI!!!!!
- made in enterocyte ER, then nascent is TG rich. mature when its picked up APOc2 and ApoE from HDL
- apoc2 activates LIPOPROTEIN lipase in capillary then hydrolyze tag to FA
- remenant chylo is taken up by liver after losing apoc2 (but still apo E present E= exit thru liver)
- release TAG in enterocyte and lip sol vitamins
fa nomenclature
- first c is anomeric, last is omega
- shorthand: # of carbons: # of double bonds
- form micelles
- adding coa to fa activates it to stay in cell since hydrophilic
albumin
carries free fa that are less than 12c long
TAG, Bile things too
- usually the 2 c spot is where essential fa are! (unsat usually while the others are sat
- can’t cross enterocyte mem so must be broken down (esp if 12c+) by bile micelles
- bile recruits panc lipase to cleave at 3 and 1 pos (preserving essential FA!!). makes di glycerol then monoglycerol.
- but immediately after crossing SI mem, FA are esterified to glycerol to make TAG then make chylomicrons
omega FA
- essential fa are linoleate and linolenate since make C12 and 15 (we can’t do past 10)
- omega 3 and 6 are counted from the back end carbon!
- omega 6 is linoleic, 3 is linolenate
- high ratio of omega 3 to 6 is best
- 3 is anti inflam, 6 is pro
trans fat
- behave like saturated FA since can stack well
- worst fats mostly in margarine, dessert, creamer etc
- labels say 0 trans fat if less than 0.5!!! so serving add up
- 2 g per day increases cardio disease by 20%
olestra
- man made where fats are linked to sucrose backbone!! CAN’T BE DIGESTED so pooped out
- stop abs of fat sol vitamins
fat sol vitamins
- vit a, d, e, K
- stored in fat so can be toxic
- A can be made from diet
- vit D made from sterol. xs leads to kidney stones and weak muscles
- vit E diet is antiox and decreases cardio and cancer
- vit K diet and made is made for clotting
FA digestion
lingual lipase would digest fa less than 12 c. gives energy to mouth cells
gastric lipase does some TAG digestion in stomach
CCK made by small intestine to stim release of bile to emulsify fat also release panc enzymes like lipase, colipse, cholesterol esterase and phospholipase A2mi
- CCK also stim release of secretin that release bicarb to raise pH for optimum Digest in SI
Km and lipase
muscle: has high affinity low km so can take up free FA even when chylomicron is low. esp cardiac
adipocytes have high Km low affinity so only chylomicron take up for storage (in insulin)
* liver has high afffinity, low km
cholesterol esterase and phopholipase A2
- ester digests partially cholesterol in animal products
- A2 is for both animal and plant. cleavage at cc2 from phospholipid!!
how are fa moved from fat to blood
GPCR CAMP and PKA turn on hormone sensitive lipase and phosophorylates perilipin. perilipin breaks adipose shell so lipase can cleave tag to FFA and glycerol
- only RBC don’t have FA transporter (into cell)
FA oxidation
- activation by adding acyl coa using acyl coa synthetase. uses 2 ATP (diff for peroxisome and mito)
- enter into inner mito mem using carnitine by carnitine acyl transferase. (then removed using carnitine palmitoyl transferase) - by malonyl coa from FA synth
- palmitoyl coa gets dehydro using acyl coa dehydrogenase to make FADH2
- isomer by ADDING WATER HYDRATION
- dehydrogenation: make an NADH
- acyl coa acetyltransferase (THIOLASE) makes acetyl coa (2c) and acyl coa (that is 2C shorter) – by ATP, NADH, FADH, acetyl coa
** to use these acetyl coa, must have oxalo from pyruvate, this we need carbs!!!
of C and cycles of b ox
- if 14 c, then 6 cycles leads to 7 acetyl coas
- each cycle makes 1 NADH (2.5 ATP) and 1 FADH2 (1.5 ATP)