Extremely high levels of NADPH in guinea pig lens: correlation with zeta-crystallin concentration

Biochem Biophys Res Commun. 1990 Mar 30;167(3):1221-8. doi: 10.1016/0006-291x(90)90654-6.


Zeta-crystallin, a major "taxon-specific" protein of the guinea pig lens, specifically binds NADPH. Analysis of pyridine nucleotide levels in guinea pig lens revealed values for NADPH approximately 50-fold higher than in other lenses. Indeed to our knowledge the values reported are higher than have been observed in any tissue. A clear correlation exists between NADPH and zeta-crystallin contents of the lens both in normal guinea pigs during development and in a line of guinea pigs with a mutation in the gene for zeta-crystallin. Heterozygotes for this mutation had a 50% reduction in NADPH, while homozygotes have only about 6% of the normal level. NADP+ levels were also markedly elevated suggesting that redox cycling of the NADPH is occurring.

MeSH terms

  • Animals
  • Cats
  • Crystallins / metabolism*
  • Glucosephosphate Dehydrogenase / metabolism
  • Guinea Pigs
  • Lens, Crystalline / metabolism*
  • NAD / metabolism
  • NADP / metabolism*
  • Oxidation-Reduction
  • Phosphogluconate Dehydrogenase / metabolism
  • Protein Binding
  • Rats
  • Rats, Inbred Strains
  • Spectrometry, Fluorescence


  • Crystallins
  • NAD
  • NADP
  • Phosphogluconate Dehydrogenase
  • Glucosephosphate Dehydrogenase