Mutagenesis and characterization of specific residues in fatty acid ethyl ester synthase: a gene for alcohol-induced cardiomyopathy.
Fatty acid ethyl ester synthase-III metabolizes both ethanol and carcinogens. Structure-function studies of the enzyme have not been performed in relation to site specific mutagenesis. In this study, three residues (Gly 32, Cys 39 and His 72) have been mutated to observe their role in enzyme activity. Gly to Gln, Cys to Trp and His to Ser mutations did not affect fatty acid ethyl ester synthase activity, but His to Ser mutant had less than 9% of control glutathione S-transferase activity. The apparent loss of transferase activity reflected a 28 fold weaker binding constant for glutathione. Thus, this study indicates that Gly and Cys may not be important for synthase or transferase activities however, histidine may play a role in glutathione binding, but it is not an essential catalytic residue of glutathione S-transferase or for fatty acid ethyl ester synthase activity.
Bora
P S
PS
Department of Internal Medicine, St. Louis University Health Sciences Center, John Cochran VA Medical Center, Missouri 63110, USA.
Miller
D D
DD
Chaitman
B R
BR
D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002310:Cardiomyopathy, Alcoholic / Q000201:enzymology* / Q000235:genetics*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D013329:Structure-Activity Relationship; D014162:Transfection
D000217:Acyltransferases; D005982:Glutathione Transferase; C043403:fatty acyl ethyl ester synthase