Age-related changes of glyceraldehyde-3-phosphate-dehydrogenase (E.C. 1.2.1.12), 3-phosphoglyceratekinase (E.C. 2.7.2.3), phosphoglyceratemutase (E.C. 2.7.5.3), and enolase (E.C. 4.2.1.11) in bovine lenses.

The specific activities of the four investigated enzymes of the carbohydrate metabolism decrease with ageing. In the old tissue, phosphoglyceratemutase and enolase sustain changes in their molecular weight, and their substrate affinity is modified.