Detailed Information

Cited 0 time in webofscience Cited 0 time in scopus
Metadata Downloads

Identification and Characterization of the Acid Phosphatase HppA in Helicobacter pylori

Authors
Ki, Mi RanYun, Soon KyuChoi, Kyung MinHwang, Se Young
Issue Date
5월-2011
Publisher
KOREAN SOC MICROBIOLOGY & BIOTECHNOLOGY
Keywords
Helicobacter pylori; acid phosphatase; HppA; ammonium ions
Citation
JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY, v.21, no.5, pp.483 - 493
Indexed
SCIE
SCOPUS
KCI
Journal Title
JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
Volume
21
Number
5
Start Page
483
End Page
493
URI
https://scholar.korea.ac.kr/handle/2021.sw.korea/112596
DOI
10.4014/jmb.1101.01017
ISSN
1017-7825
Abstract
An acid phosphatase (HppA) activated by NH4Cl was purified 192- and 34-fold from the periplasmic and membrane fractions of Helicobaeter pylori, respectively. SDS-polyacrylamide gel electrophoresis revealed that HppA from the latter appears to be several kilodaltons larger in molecular mass than from the former by about 24 kDa. Under acidic conditions (pH <= 4.5), the enzyme activity was entirely dependent on the presence of certain mono- and/or divalent metal cations (e.g., K+, NH4+, and/or Ni2+). In particular, Ni2+ appeared to lower the enzyme's K-m for the substrates, without changing V-max. The purified enzyme showed differential specificity against nucleotide substrates with pH; for example, the enzyme hydrolyzed adenosine nucleotides more rapidly at pH 5.5 than at pH 6.0, and vice versa for CTP or TTP. Analyses of the enzyme's N-terminal sequence and of an HppA(-) H. pylori mutant revealed that the purified enzyme is identical to rHppA, a cloned H. pylori class C acid phosphatase, and shown to be the sole bacterial 5'-nucleotidase uniquely activated by NH4Cl. In contrast to wild type, HppA(-) H. pylori cells grew more slowly. Strikingly, they imported Mg2+ at a markedly lowered rate, but assimilated urea rapidly, with a subsequent increase in extracellular pH. Moreover, mutant cells were much more sensitive to extracellular potassium ions, as well as to metronidazole, omeprazole, or thiophenol, with considerably lowered MIC values, than wild-type cells. From these data, we suggest that the role of the acid phosphatase HppA in H. pylori may extend beyond 5'-nucleotidase function to include cation-flux as well as pH regulation on the cell envelope.
Files in This Item
There are no files associated with this item.
Appears in
Collections
College of Science and Technology > Department of Biotechnology and Bioinformatics > 1. Journal Articles

qrcode

Items in ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.

Altmetrics

Total Views & Downloads

BROWSE