Comparative Enzymology of the Glyceraldehyde 3-Phosphate Dehydrogenases from Pisum sativum

Glyceraldehyde 3-phosphate dehydrogenases (EC 1.2.1.12 and 1.2.1.13) have been purified from the seed, root, etiolated, and green shoot of peas (Pisum sativum). These enzymes are tetramers of 140,000 daltons, with subunits of 35,000 daltons. The enzymes differ in isoelectric point. The seed enzyme has a pI of 5.1, and the root enzyme has a pI of 4.5. The cytoplasmic enzyme from etiolated shoots is slightly acidic with a pI of 5.7 to 6.1 and is found in two separable forms. The chloroplast enzyme (from green shoots) is most basic with a pI of 8.0.