Catalytic Properties for Naphthoquinones and Partial Primary Structure of Rabbit Heart Acetohexamide Reductase

概要

論文の詳細を見る
The catalytic properties of rabbit heart acetohexamide reductase (RHAR) for naphthoquinones were examined. RHAR efficiently reduced 1,4-naphthoquinone and juglone (5-hydroxy-1,4-naphthoquinone), whereas it had little or no ability to reduce menadione (2-methyl-1,4-naphthoquinone) or plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone). The structural requirements for these four naphthoquinones and one acetohexamide analog, and the kinetic mechanism for the inhibition of acetohexamide reduction by juglone led us to conclude that the 2-methyl group of menadione and plumbagin prevents access of the substrates to the catalytic site of RHAR. Five of six peptides derived from RHAR showed 30-42% residue identities with regions in the amino acid sequence of mouse lung carbonyl reductase (MLCR) belonging to the short-chain dehydrogenase/reductase (SDR) family. The catalytically important residues (Arg-39,Ser-136,Tyr-149 and Lys-153) of MLCR were found in the peptide sequences of RHAR, despite the low residue identities between the two enzymes. RHAR is probably bast classified as a member of the SDR family similar to MLCR.
公益社団法人日本薬学会の論文
2000-02-01