liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Rates of elementary catalytic steps for different metal forms of the family II pyrophosphatase from Streptococcus gordonii
Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
Show others and affiliations
2004 (English)In: Biochemistry, ISSN 0006-2960, Vol. 43, no 4, 1065-1074 p.Article in journal (Refereed) Published
Abstract [en]

Soluble inorganic pyrophosphatases (PPases) form two nonhomologous families, denoted I and II, that have similar active-site structures but different catalytic activities and metal cofactor specificities. Family II PPases, which are often found in pathogenic bacteria, are more active than family I PPases, and their best cofactor is Mn2+ rather than Mg2+, the preferred cofactor of family I PPases. Here, we present results of a detailed kinetic analysis of a family II PPase from Streptococcus gordonii (sgPPase), which was undertaken to elucidate the factors underlying the different properties of family I and 11 PPases. We measured rates of PPi hydrolysis, PPi synthesis, and P-i/water oxygen exchange catalyzed by sgPPase with Mn2+, Mg2+, or Co2+ in the high-affinity metal-binding site and Mg2+ in the other sites, as well as the binding affinities for several active-site ligands (metal cofactors, fluoride, and P-i). On the basis of these data, we deduced a minimal four-step kinetic scheme and evaluated microscopic rate constants for all eight relevant reaction steps. Comparison of these results with those obtained previously for the well-known family I PPase from Saccharomyces cerevisiae (Y-PPase) led to the following conclusions: (a) catalysis by sgPPase does not involve the enzyme-PPi complex isomerization known to occur in family I PPases, (b) the values of k(cat) for the magnesium forms of sgPPase and Y-PPase are similar because of similar rates of bound PPi hydrolysis and product release, (c) the marked acceleration of sgPPase catalysis in the presence of Mn2+ and Co2+ results from a combined effect of these ions on bound PPi hydrolysis and P-i release, (d) sgPPase exhibits lower affinity for both PPi and P-i, and (e) sgPPase and Y-PPase exhibit similar values of k(cat)/K-m, which characterizes the PPase efficiency in vivo (i.e., at nonsaturating PPi concentrations).

Place, publisher, year, edition, pages
2004. Vol. 43, no 4, 1065-1074 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-46307DOI: 10.1021/bi0357513OAI: diva2:267203
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2011-01-12

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Vener, Alexander
By organisation
Faculty of Health SciencesCell Biology
In the same journal
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 11 hits
ReferencesLink to record
Permanent link

Direct link