Enzymes for Module 2

Hexokinase

adds a phosphate group to glucose, yielding G6P and using 1 ATP. Inhibited by G6P and ATP.

Phosphoglucoisomerase

changes G6P into F6P, an isomer

Phosphofructokinase-1

adds a second phosphate to F6P, yielding F1,6BP using 1 ATP. Inhibited by ATP and citrate. Activated by F2,6BP and AMP.

Aldolase

C-C cleavage of F1,6BP, yielding a 3C GAP and DHAP (isomers)

Triosephosphate isomerase

converts DHAP molecules into GAP, should have 2 GAP going forward

Glyceraldehyde-3-phosphate dehydrogenase

REDOX reaction, GAP is oxidized and NAD is reduced yielding 1,3-bisphosphoglycerate and NADH

Phosphoglycerokinase

1,3-bisphosphoglycerate is converted into 3-phosphoglycerate, yielding 1 ATP (x2)

Phosphoglyceromutase

rearranges the phosphate group on 3-phosphoglycerate, yielding 2-phosphoglycerate

Enolase

converts 2-phosphoglycerate into PEP, producing H2O

Pyruvate kinase

transfers a phosphate from PEP to ADP, yielding ATP and pyruvate (x2). Inhibited by ATP and acetyl-CoA. Activated by F1,6BP.

Pyruvate carboxylase

converts pyruvate into oxaloacetate. Activated by acetyl-CoA

Phosphophoenolpyruvate carboxykinase (PEPCK)

converts oxaloacetate into PEP, using a GTP.

Fructose-1,6-biphosphatase

removes the 1’ phosphate from F1,6BP via hydrolysis, yielding F6P. Inhibited by F2,6BP and AMP.

Glucose-6-phosphatase

removes the phosphate group from G6P, yielding glucose.

Citrate synthase

condensation of acetyl-CoA with oxaloacetate to form citrate. Inhibited by ATP, NADH, citrate, and succinyl-CoA. Activated by oxaloacetate.

Acontinase

removal and addition of water from 3’ to 4’ of citrate, yielding isocitrate (an isomer)

Isocitrate dehydrogenase

REDOX reaction, oxidative decarboxylation of isocitrate to form alpha-ketoglutarate. NADH and CO2 are produced. Inhibited by ATP and NADH. Activated by ADP and calcium ions.

Alpha-ketoglutarate dehydrogenase

REDOX reaction, alpha-ketoglutarate is oxidized and NAD is reduced to NADH. CO2 is removed, CoA is added, yielding 4C succinyl-CoA. Inhibited by ATP, NADH, and succinyl-CoA. Activated by calcium ions.

Succinyl-CoA synthase

CoA is removed from succinyl-CoA to form succinate. Substrate-level phosphorylation produces GTP.

Succinate dehydrogenase

REDOX reaction, succinate is oxidized to fumarate while FAD is reduced to FADH2.

Fumarase

reversible hydration of fumarate to yield L-malate

Malate dehydrogenase

REDOX reaction, malate is oxidized to oxaloacetate while NAD is reduced to NADH

NADH-coenzyme Q oxidation complex (NADH dehydrogenase)

transfers NADH electrons to ubiquinone (Complex I)

Succinate-coenzyme Q oxidoreductase complex (succinate dehydrogenase)

succinate is oxidized to fumarate while FAD is reduced to FADH2. CoQH2 is formed.

Coenzyme Q-cytochrome c oxireductase complex

transfer electrons from ubiquinol to cytochrome c

Cytochrome c oxidase

transfer electrons are transferred from cytochrome c to Fe in cytochrome a and a3, then Cu transfers electrons to O2, forming H2O

RNA Polymerase I

Synthesizes ribosomal RNA (rRNA).

RNA Polymerase II

Synthesizes all protein-coding messenger RNA (mRNA) and several small non-coding RNAs.

RNA Polymerase III

Synthesizes transfer RNA (tRNA) and some small rRNAs.

Acyl-CoA dehydrogenase

removes two hydrogen atoms from the fatty acid, creating a double bond between the second and third carbons (the α and β carbons). This reaction transfers electrons to FAD, creating FADH₂.

Enoyl-CoA hydratase

adds a water molecule across the double bond created in step one. This process attaches a hydroxyl (-OH) group to the β-carbon

β-hydroxyacyl-CoA dehydrogenase

oxidizes the newly added -OH group by removing two hydrogens. This converts the -OH into a ketone (=O) group and transfers electrons to NAD⁺, forming NADH

Thiolase

(C-C cleavage) uses a molecule of CoA to break the bond between the α and β carbons. This releases one molecule of acetyl-CoA (a two-carbon unit) and leaves behind a fatty acyl-CoA chain that is now two carbons shorter

Glycolysis Equation

TCA Cycle Equation

Respiration net equation