Separation of water-soluble protein of bovine lenses by Sepharose 6-B and subsequent measurement of the enzyme activities of aldose reductase, sorbitol dehydrogenase, and ketohexokinase show an enzyme heterogeneity for all three enzymes of the sorbitol pathway. While for SDH four modifications could be detected, AR and KHK showed at least two modifications. As concerns SDH and KHK, the arrangement within the elution profile and distribution of the activity among the individual modifications vary with age. Considering the results of Bous et al. for PFK and of Banroques et al. for aldolase, our findings on enzyme modifications may be considered as so-called metazymes originating from postsynthetic changes of the enzyme protein.

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