Evidence for arylamine N-acetyltransferase activity in the bacterium Helicobacter pylori.
N-Acetyltransferase activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori from gastroduodenal disease patients. The N-acetyltransferase activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. The N-acetyltransferase activities from a number of Helicobacter pylori samples were found to be 0.91 +/- 0.12 nmole/min/mg protein for the acetylation of 2-aminofluorene and 0.75 +/- 0.22 nmole/min/mg protein for the acetylation of p-aminobenzoic acid. The apparent K(m) and V(max) values obtained were 1.10 +/- 0.08 mM and 2.34 +/- 0.14 nmol/min/mg protein for 2-aminofluorene, and 0.92 +/- 0.09 mM and 2.08 +/- 0.16 nmol/min/mg protein for p-aminobenzoic acid. The optimal pH value for the enzyme activity was 6.0 for both substrates tested. The optimal temperature for enzyme activity was 37 degrees C for both substrates. The N-acetyltransferase activity was inhibited by iodacetamide: at 0.25 mM iodacetamide, activity was reduced 50% and 1.0 mM iodacetamide inhibited activity more than 90%. Among a series of divalent cations and salts, Cu2+ and Zn2+ were demonstrated to be the most potent inhibitors. Among the protease inhibitors, only ethylenediaminetetraacetic acid significantly protected N-acetyltransferase. Iodoacetic acid, in contrast to the other agents, markedly inhibited N-acetyltransferase. This is the first demonstration of acetyl CoA:arylamine N-acetyltransferase activity in Helicobacter pylori.
Chung
J G
JG
Department of Medicine, China Medical College, Taichung, Taiwan, ROC.
Wang
H H
HH
Tsou
M F
MF
Hsieh
S E
SE
Lo
H H
HH
Yen
Y S
YS
Chang
S S
SS
Wu
L T
LT
Lee
J H
JH
Hung
C F
CF
D010129:4-Aminobenzoic Acid / Q000737:chemistry / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000378:metabolism; D000107:Acetylation; D001191:Arylamine N-Acetyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000633:toxicity; D005449:Fluorenes / Q000737:chemistry / Q000378:metabolism*; D016480:Helicobacter pylori / Q000201:enzymology* / Q000648:ultrastructure; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007460:Iodoacetamide / Q000633:toxicity; D007700:Kinetics; D011480:Protease Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
D004791:Enzyme Inhibitors; D005449:Fluorenes; D011480:Protease Inhibitors; C012177:2-aminofluorene; D000105:Acetyl Coenzyme A; D001191:Arylamine N-Acetyltransferase; D010129:4-Aminobenzoic Acid; D007460:Iodoacetamide