Initial characterization of aldehyde dehydrogenase from rat testis cytosol

• Published in: Biological chemistry Hoppe-Seyler Vol. 371; no. 1; p. 95
• Main Authors: Bedino, S, Testore, G, Obert, F
• Format: Journal Article
• Language: English
• Published: Germany 01-01-1990
• Subjects: Aldehyde Dehydrogenase - antagonists & inhibitors; Aldehyde Dehydrogenase - isolation & purification; Aldehyde Dehydrogenase - metabolism; Animals; Calcium - pharmacology; Cytosol - enzymology; Hydrogen-Ion Concentration; Kinetics; Magnesium - pharmacology; Male; Rats; Rats, Inbred Strains; Temperature; Testis - enzymology
• ISSN: 0177-3593
• DOI: 10.1515/bchm3.1990.371.1.95

Aldehyde dehydrogenase was purified 187-fold from cytosol of rat testis by chromatographic methods and gel filtration with a yield of about 50%. The enzyme exhibits absolute requirement for exogenous sulfhydryl compounds and strong dependence on temperature. Addition of 0.4mM Ca2 or Mg2 ions results in 50% inhibition. Optimally active at pH 8.5 and 50 degrees C, aldehyde dehydrogenase displays broad substrate specificity; saturation curves with acetaldehyde and propionaldehyde are non-hyperbolic, with Hill coefficients comprised between 0.8 and 0.7. Strong substrate inhibition can be observed with both aromatic and long-chain alyphatic aldehydes. According to mathematical models, Km decreases from 246 microM for acetaldehyde to 4 microM for capronaldehyde and Ki decreases from about 4mM for butyraldehyde to 0.2 mM for capronaldehyde.