biochem unit 3 week 9

the end products of glycolysis are

2 ATP, 2 NADH, and 2 pyruvate

three regulatory enzymes of glycolysis

glucokinase/hexokinase, phosphofructokinase (PFK1), and pyruvate kinase

What do glucokinase/hexokinase do?

phosphorylate glucose to glucose-6-phosphate to keep it in the cell

where is glucokinase most present? hexokinase?

liver and pancreas beta cells, most other cells

glucokinase has a ___ Km and thus ___ affinity than hexokinase in the liver when glucose concentration is low

higher Km, lower affinity

hexokinase has a ___ Km and thus ___ affinity than glucokinase in the liver when glucose concentration is low

lower Km, higher affinty

glucokinase has a high affinity for glucose when glucose concentrations are ___

high

hexokinase acts on (phosphorylates) glucose in the liver at a very ___ range of ___ concentrations

small, lower

activators of phosphofructokinase I (PFK) and their indication

AMP and fructose 2,6 biphosphate, low levels of energy

after hexokinase or glucokinase phosphorylate glucose into glucose-6-phosphate, it is ___

isomerized into fructose-6-phosphate

fructose-1,6-bisphosphate is ___ by ___ into ___

cleaved by aldolase B into dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.

PK1 phosphorylates ___ into ___

fructose 6-phosphate to fructose 1, 6-bisphosphate.

inhibitors of PFK1 and what they indicate

ATP and citrate, high levels of energy in the cell

glucokinase and hexokinase are ___, which means ___

isozymes, they have different AA sequences but catalyze the same reaction

activators of PFK1 and what they each indicate

AMP (low energy levels in cell) + fructose 2,6 bisphosphate (high levels of fructose-6-phosphate therefore glucose therefore potential energy in the cell)

activator of pyruvate kinase and what it indicates

fructose 1,6 bisphosphate (high levels of fructose-6-phosphate therefore glucose therefore potential energy in the cell)

inhibitors of pyruvate kinase and what they indicates

ATP (high energy levels in cell), alanine (high levels of pyruvate because it’s a product of pyruvate transamination for use in other pathways), glucagon-mediated phosphorylation (glucagon signals a fasting state)

What does anaerobic glycolysis produce?

lactate

Why is lactate produced in anaerobic glycolysis?

It can generate NAD+

3 things that can happen after pyruvate is produced

• Enter the TCA cycle through the pyruvate dehydrogenase complex

• Be converted to lactate under anaerobic conditions

• Be transaminated to alanine 

activators of PDH

pyruvate and NAD+

inhibitors of PDH

ATP, acetyl CoA, and NADH

results of PDH complex

pyruvate is converted into acetyl CoA

PDH is inactivated by, via

phosphorylation, PDH kinase

deactivated PDH is reactivated by

PDH phosphotase

cofactor required by PDH

thiamin

TCA cycle is responsible for generating over ____ of the ATP from the oxidation of fuels.

half

net energy production of TCA cycle

three NADH, one FADH2, two carbon dioxide, and one GTP for every acetyl-CoA that enters.

activators, inhibitors of isocitrate dehydrogenase

ADP and Ca2+, NADH

activators, inhibitors of alpha-ketoglutarate dehydrogenase.

Ca2+, NADH and arsenite

cofactors required by alpha-ketoglutarate dehydrogenase

thiamine, lipoate, FAD

inhibitor of iconitase

fluoroacetate

inhibitor of succinate dehydrogenase

malonate

which substrate is the starting point for the TCA

acetyl CoA

pyruvate must be ___ by ___ into ___ between glycolysis and TCA

oxidized by PDH into acetyl CoA