Ocular NAD-dependent alcohol dehydrogenase and aldehyde dehydrogenase in the baboon

Abstract

Isoelectric focusing (IEF) techniques and spectrophotometric analyses were used to examine the distribution and properties of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) isozymes in ocular tissue of olive and yellow baboons. Cornea extracts exhibited very high specific activities of the 'stomach-specific' ADH and ALDH isozymes (designated ADH-3 and ALDH-III respectively), and were devoid of the major liver and kidney isozymes. Lens extracts exhibited lower activities of ADH-3 and ALDH-III, and also showed significant activity of ALDH-II (the major liver cytosolic isozyme) and a group of 'lens-specific' ALDHs of low isoelectric point. Extracts of baboon retina also exhibited ADH-3 and ALDH-III activities, together with activities of the major liver cytosolic (ALDH-II) and mitochondrial (ALDH-I) isozymes of ALDH; and ADH-5 (or chi-ADH) activity. Evidence was obtained for individual variation of ALDH-III activity in the lens. An electrophoretic variant for ADH-3 indicated genetic identity of the major stomach and ocular ADH isozyme. The catalytic properties of the high specific activity corneal ADH and ALDH isozymes indicated a role in the detoxification of lipid peroxidation by-products.