Extremely high levels of NADPH in guinea pig lens: correlation with zeta-crystallin concentration.
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.
Rao
P V
PV
Laboratory of Mechanisms of Ocular Diseases, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892.
Zigler
J S
JS
D000818:Animals; D002415:Cats; D003459:Crystallins / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006168:Guinea Pigs; D007908:Lens, Crystalline / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011919:Rats, Inbred Strains; D013050:Spectrometry, Fluorescence
D003459:Crystallins; D009243:NAD; D009249:NADP; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase