Possible involvement of cysteine and histidine residues in the (NH4+ + Na+)-activated ATPase of an anaerobic alkaliphile, Amphibacillus xylanus.
Effect of various inhibitors on the (NH4+ + Na+)-activated ATPase of an anaerobic alkaliphile, Ep01(a strain of Amphibacillus xylanus), was examined. Among the chemicals tested, the enzyme was drastically inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate. The ATPase activity of the enzyme, which was inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate, was remarkably restored by beta-mercaptoethanol and hydroxylamine, respectively, suggesting the involvement of cysteine and histidine residues in the enzyme activity. Analysis of the inhibition kinetics by diethyl pyrocarbonate indicated that modification of a single histidine residue per ATPase molecule was sufficient to inactivate the enzyme.
Okano
Y
Y
Department of Chemistry, Faculty of Science, Chiba University, Yayoi, Chiba 263, Japan.
Maeki
T
T
Koyama
N
N
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000201:enzymology*; D001665:Binding Sites; D003545:Cysteine; D006639:Histidine; D013329:Structure-Activity Relationship
D006639:Histidine; D000251:Adenosine Triphosphatases; D003545:Cysteine