MUSCLE PHYSIOLOGY

Detailed explanation-1: -Triosephosphate isomerase (TIM) is a perfectly evolved enzyme which very fast interconverts dihydroxyacetone phosphate and D:-glyceraldehyde-3-phosphate. Its catalytic site is at the dimer interface, but the four catalytic residues, Asn11, Lys13, His95 and Glu167, are from the same subunit.

Detailed explanation-2: -Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC:1.2. 1.12) is an important enzyme in the glycolysis process. In the presence of inorganic phosphate (Pi), GAPDH catalyzes the conversion of D-glyceraldehyde-3-phosphate (G3P) to 1, 3-diphosphoglycerate (BPG), accompanying the reduction of NAD+ to NADH.

Detailed explanation-3: -Triosephosphate isomerase (TIM)1 catalyzes the stereospecific 1, 2-proton shift at dihydroxyacetone phosphate (DHAP) to give (R)-glyceraldehyde 3-phosphate through a pair of isomeric enzyme-bound cis-enediolate phosphate reaction intermediates (Scheme 1) (2).