Initial characterization of aldehyde dehydrogenase from rat testis cytosol.
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.
Bedino
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S
Dipartimento di Medicina e Oncologia Sperimentale, Università di Torino, Italy.
Testore
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G
Obert
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F
D000444:Aldehyde Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013696:Temperature; D013737:Testis / Q000201:enzymology*
D000444:Aldehyde Dehydrogenase; D008274:Magnesium; D002118:Calcium