BIOC 503 - Regulation of Glycolysis, TCA Cycle, ETC/Oxidative Phosphorylation

interdependent

the regulation of TCA cycle, glycolysis, and ETC is ____

cytoplasm

glycolysis location

mitochondrial matrix

TCA cycle location

inner mitochondrial membrane

ETC location

irreversible, favorable

biochemical pathways are usually regulated at ___ and highly thermodynamically ___ steps

allosteric enzymes

enzymes regulating the irreversible, highly thermodynamically favorable steps of biochemical pathways

availability, accumulation

allosteric enzymes regulating biochemical pathways are activated by substrate ___ and inhibited by product ___

reversibly, non-covalently

allosteric modulators bind ___ and ___ to enzymes

allosteric inhibitors

Bind to enzyme and shift it to a conformation with a LOWER affinity for the substrate

allosteric activators

bind to enzyme and shift it to a conformation with HIGHER affinity for the substrate

AMP, ADP, ATP

Glycolysis is activated by elevated ___ and ___, and inhibited by elevated ___

low

glycolysis also increases oxygen availability in tissues when the O2 levels are ___ (due to elevation for example): ETC decreases due to lack of O2, thus ATP levels decreases, so glycolysis upregulated to make more ATP

• also increases levels of by-product 2,3 biphosphoglycerate

2,3 biphosphoglycerate

by product of glycolysis whose production increases at low O2 levels

• binds to hemoglobin in tissues decreasing affinity for O2

• more oxygen is then available to produce more ATP

PD kinase

enzyme regulating the activity of the pyruvate dehydrogenase complex

• activated by: ATP, NADH, acetyl-CoA (aka deactivate PDH complex and inhibit TCA cycle)

• inhibited by: ADP, NAD+, CoA, pyruvate (aka activate PDH complex and enhance TCA cycle)

phosphorylated, dephosphorylated

PDH complex is inactive when it is ___ by PD kinase

PDH is active when it is __ by PD phosphatase

inhibits

too much ATP and NADH = ___ TCA cycle

activates

too much AMP or ADP = ATP is being used more, need to make more, ___ TCA cycle

insulin

__ activates biosynthetic pathways that will require ATP

calcium

__ is released from ER upon muscle contraction, which requires ATP, and thus ACTIVATES TCA cycle

co-regulated

Glycolysis, TCA cycle, and oxidative phosphorylation are ___ by ATP, ADP, AMP, and NADH levels in the cells

hypoxia-inducible factor 1

aka HIF-1

• activates glycolysis under hypoxic (LOW O2) conditions

• upregulate gene expression for glucose transporters, glycolytic enzymes, and lactate dehydrogenase

• downregulate gene expression for promoter of PD kinase, which innibit TCA cycle and upregulate glycolysis