Six-base deletion occurring in messages of human cytochrome P-450 in the CYP2C subfamily results in reduction of tolbutamide hydroxylase activity.
We isolated and expressed a clone, hPA6, possibly corresponding to the CYP2C9 cDNA. Compared with the other CYP2C9 cDNA clones, hPA6 showed a 6-nucleotide deletion near its middle. From the same cDNA library, we could also isolate another cDNA clone, named hPA22, which retained the 6 bases. For clarification of the effect of the 2-amino acid deletion resulting from the 6-base deletion on enzymatic activities, both clones were expressed in yeast. The expressed enzymes showed tolbutamide hydroxylase activities, and these activities were inhibited by antibodies against P-450-HM2, a probable CYP2C9. The activity of the enzyme encoded by hPA6 was lower than that encoded by hPA22; thus the 2-amino acid deletion in the CYP2C9 reduced the enzymatic activity.
Ohgiya
S
S
Government Industrial Development Laboratory-Hokkaido, Sapporo, Japan.
Komori
M
M
Ohi
H
H
Shiramatsu
K
K
Shinriki
N
N
Kamataki
T
T
D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism*; D004247:DNA; D006801:Humans; D008861:Microsomes / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010957:Plasmids; D012441:Saccharomyces cerevisiae; D017384:Sequence Deletion; D014044:Tolbutamide / Q000378:metabolism
D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D014044:Tolbutamide; D006899:Mixed Function Oxygenases; C053553:tolbutamide 4-hydroxylase