biochem II exam 2

what 3 enzymes are required for glycogenolysis

glycogen phosphorylase

phosphoglucomutase

glycogen debranching enzyme

what does glycogen phosphorylase do

converts glycogen to G1P and glycogen (n-1)

what do phosphorylases use to attack

Pi

what do phosphatases use to attack

H2O

what vitamin cofactor does G1P require

pyridoxal phosphate (PLP)

what is PLP derived from

pyridoxine (vit B6)

what does phosphoglucomutase do

converts G1P to G6P

what does glycogen debranching enzyme do

shifts 3 glycosyl units from one strand to another to hydrolyzes remaining alpha (1-6) sugar

what is the substrate for glycogen synthesizing enzyme

UDP-glucose

what 3 enzymes are required for glycogen synthesis

UDP-glucose phosphorylase

glycogen synthase

glycogen branching enzyme

what does UDP-glucose phosphorylase do

forms UDP-glucose

what does glycogen synthase do

forms UDP + glycogen (n+1)

what does glycogen branching enzyme do

transfers segment of alpha (1-4) linked sugars to an alpha (1-6) linkage

when glycogen phosphorylase is phosphorylated is it active or inactive

active

when glycogen synthase is phosphorylated is it active or inactive

inactive

what does insulin activate in glycogen metabolism

phosphatase

what does glucagon and epinephrine activate in glycogen metabolism

kinase

what does glucose do to glycogen phosphorylase

inactivates

what does epinephrine do to glycogen breakdown

stimualtes

what does epinephrine do to glycogen synthesis

inhibits

what does insulin do to glycogen synthesis

stimulates

what does insulin do to glycogen breakdown

inhibits

what are the 2 things pyruvate can be used for

make glucose

make acetyl coa

what enzyme converts pyruvate to acetyl coa

pyruvate dehydrogenase complex

what does pyruvate dehydrogenase complex do

oxidative decarboxylation of pyruvate to acetyl coa

what 3 enzymes are in the pyruvate dehydrogenase complex

pyruvate dehydrogenase

dihydrolipoyl transacetylase

dihydrolipoyl dehydrogenase

what cofactor does pyruvate dehydrogenase require

TPP cofactor

what does pyruvate dehydrogenase do

decarboxylation of pyruvate to aldehyde

what cofactor does dihydrolipoyl transacetylase require

lipoate cofactor

what does dihydrolipoyl transacetylase do

oxidation of aldehyde to carboxylic acid

formation of acetyl coa

what cofactors does dihydrolipoyl dehydrogenase require

FAD and NAD+

what does dihydrolipoyl dehydrogenase do

reoxidation of lipoamide cofactor

formation of NADH and regeneration of oxidized FAD cofactor

product inhibitors of pyruvate dehydrogenase reaction

acetyl coa and NADH

feedback inhibitors of pyruvate dehydrogenase reaction

ATP and GTP

feedback activators of pyruvate dehydrogenase reaction

AMP

what does high ATP lead to in pyruvate dehydrogenase reaction

less acetyl coa

what does ATP do to PDH kinase

activates

what does high AMP lead to in pyruvate dehydrogenase reaction

more acetyl coa

what inhibits PDH kinase

pyruvate, ADP, NAD+, Coa-Sh

what does phosphorylation of E1 do to PDH

inactivates

what does dephosphorylation of E1 do to PDH

activates

what happens to acetyl coa and oxaloacetate in TCA

bond formed via condensation between them

citrate synthase helps form citrate

what happens once citrate is formed in TCA

isomerized via dehydration/rehydration so there is a secondary alcohol

what happens once citrate is isomerized to isocitrate in TCA

oxidized via hydride transfer to NAD+ or NADP+ forming oxalosuccinate

what happens to oxalosuccinate in TCA

decarboxylated and rearranged to alpha-ketoglutarate

what happens to alpha-ketoglutarate in TCA

reacts with alpha-ketoglutarate dehydrogenase complex to make NADH

results in succinyl coa

what happens to succinyl coa in TCA

reacts with succinyl coa synthase to form succinate

what happens to succinate in TCA

reacts with succinate dehydrogenase to form fumarate

generates FADH2

what happens to fumarate in TCA

reacts with fumarase forming L-malate

what happens to L-malate in TCA

reaction with malate dehydrogenase forming oxaloacetate and NADH

products of TCA

2 CO2, 3NADH, FADH2, GTP, CoA, 3H+

what reactions is TCA regulated at

citrate synthase

isocitrate dehydrogenase

alpha-ketoglutarate dehydrogenase

what are the allosteric inhibitors of citrate synthase

ATP, NADH, succinyl coa

allosteric inhibitor of isocitrate dehydrogenase

ATP

allosteric activator of isocitrate dehydrogenase

ADP

product inhibitor of isocitrate dehydrogenase

NADH

allosteric inhibitors of alpha ketoglutarate dehydrogenase

ATP, GTP

allosteric activator of alpha ketoglutarate dehydrogenase

AMP

product inhibitors of alpha ketoglutarate dehydrogenase

NADH, succinul coa

what is citrate used to make

fatty acids and sterols

what is alpha ketoglutarate used to make

amino acids, purines, pyrimidines

what is succinyl coa used to make

porphyrin ring of heme

what is oxaloacetate used to make

glucose, amino acids, purines, pyrimidines

what do epinephrine and glucagon do to lipolysis in adipose tissue

stimulate

what does insulin do to lipolysis in adipose tissue

inhibits

what does phosphorylation of kinase do to tracylglycerol lipase

activates

what does phosphorylation of phosphatase do to tracylglycerol lipase

inactivates

what is beta oxidation

process of fatty acid degradation

reaction pathway of beta oxidation

oxidation, hydration, oxidation, thiolysis

what happens in the first oxidation reaction of beta oxidation

acyl coa oxidated by acyl coa dehydrogenase to trans enoyl coa

what cofactor does acyl coa dehydrogenase require

FAD cofactor

what happens in hydration reaction of beta oxidation

trans enoyl coa hydrate by enoyl coa hydratase to L-3- hydroxyacylcoa

what happens in second oxidation reaction of beta oxidation

L-3-hydroxyacyl coa oxidized by L-hydroxylacyl coa dehydrogenase to 3-ketoacyl coa

what cofactor does L-hydroxyacyl coa dehydrogenase require

NAD+

what happens in thiolysis reaction in beta oxidation

acetyl coa cleaved off of 3-ketoacyl coa by beta ketothiolase

5 cofactors required for pyruvate dehydrogenase complex

TPP, lipoate, FAD, NAD+, coa