|
KMID : 0545120090190121565
|
|
Journal of Microbiology and Biotechnology
2009 Volume.19 No. 12 p.1565 ~ p.1568
|
|
|
Helicobacter pylori Urease May Exist in Two Forms: Evidence from the Kinetic Studies
|
|
Gang Jin-Gu
Yun Soon-Kyu
Hwang Se-Young
|
|
|
Abstract
|
|
|
|
Purified Helicobacter pylori urease displayed a sigmoid curve in the plot of velocity versus [S] at urea concentrations less than 0.1 mM. Under condition that preservatives, glycerol or polyethylene glycol (PEG), were added to the enzyme reaction, then substrate was hydrolyzed consistent with Michaelis-Menten kinetics with a Km of 0.21 ± 0.06 mM and a Vmax of 1200 ± 300 μmol min-1 mg-1. However, at saturating substrate concentrations, the kinetic parameters of H. pylori urease were unaffected by the presence of the preservatives and enzyme catalysis conformed to Michaelis-Menten kinetics. And, Hill coefficients of the enzyme-catalyzed urea hydrolysis in the presence and absence of PEG were 1 and 2, respectively. Based on these findings, we suggest that H. pylori urease may exist in aggregated and dissociated forms, each with intact function but differing kinetics that may be of importance in maximizing urea breakdown at varying urea concentrations in vivo.
|
|
|
KEYWORD
|
|
|
Helicobacter pylori, urease, kinetics
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
  
|