AUTOCATALYTIC MODIFICATION OF HUMAN CARBONYL REDUCTASE BY 2-OXOCARBOXYLIC ACIDS

Carbonyl reductase occurs in multiple molecular forms. Sequence analys is has yielded a carboxyethyllysine residue in one of the enzyme forms , suggesting that pyruvate has been incorporated in a posttranslationa l enzymatic reaction [Krook, M., Ghosh, D., Stromberg R., Carlquist, M . and Jornvall, H. (1993) Proc. Natl. Acad. Sci. USA 90, 502-506]. Usi ng highly purified carbonyl reductase from human brain we show that py ruvate and other 2-oxocarboxylic acids are bound to the enzyme in an a utocatalytic reaction. The resulting enzyme forms were indistinguishab le from the native enzyme forms by electrophoresis and isoelectric foc using.