Human lens enzyme alterations with age and cataract: glyceraldehyde-3-P dehydrogenase and triose phosphate isomerase

Curr Eye Res. 1986 Feb;5(2):119-26. doi: 10.3109/02713688609015100.


The isoelectric point distribution of G-3-P DH and TPI from human lenses was examined as a function of age and cataract formation. Both enzymes exhibited progressive heterogeneity with age and a shift towards an acidic charge. Little qualitative differences in the pI profiles of G-3-P DH and TPI were found to distinguish mixed cataracts from age comparable normal lenses. While the most alkaline form of G-3-P DH required less HAsO4= for optimal activity, no other kinetic property, i.e. Km substrate, cofactor and inhibitors distinguished any of the charge forms of G-3-P DH. All metaor isozyme forms of TPI had the same Km substrate in the forward and reverse reaction direction. The most acidic forms of G-3-P DH and TPI were less stable to increased temperatures than their more alkaline counterparts suggesting a decreased stability.

MeSH terms

  • Adolescent
  • Adult
  • Aging
  • Carbohydrate Epimerases / metabolism*
  • Cataract / enzymology*
  • Child
  • Female
  • Fetus
  • Glyceraldehyde-3-Phosphate Dehydrogenases / metabolism*
  • Humans
  • Infant
  • Isoelectric Focusing
  • Lens, Crystalline / enzymology
  • Lens, Crystalline / growth & development*
  • Middle Aged
  • Pregnancy
  • Thermodynamics
  • Triose-Phosphate Isomerase / metabolism*


  • Glyceraldehyde-3-Phosphate Dehydrogenases
  • Carbohydrate Epimerases
  • Triose-Phosphate Isomerase