HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sperow, J. W. Articles by Butler, L. G. Search for Related Content PubMed PubMed Citation Articles by Sperow, J. W. Articles by Butler, L. G. Social Bookmarking                      What's this?

Yeast Inorganic Pyrophosphatase

VI. STUDIES ON SPECIFICITY AND MECHANISM

From the ¹ From the Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907

Analogs of PP_i in which the bridge oxygen is replaced by imido, methylene, or ,-glycol linkages are not substrates for crystalline yeast inorganic pyrophosphatase. Apparent competitive inhibition of Mg²⁺-activated PP_i hydrolysis is observed with imidodiphosphate and with the C₁ and C₂ members of the ,-glycol diphosphate series, methanediol diphosphate and 1,2-ethanediol diphosphate. Methylene diphosphonate, two of its C-substituted derivatives, and the C₃ and C₄ members of the ,-glycol diphosphate series are not inhibitory under the conditions employed, which are near optimal for PP_i hydrolysis. Specificity for inhibitors is not markedly broader than specificity for substrate, and, like substrate specificity, is maximal in the presence of Mg²⁺ as activating ion.

No evidence could be obtained for phosphoryl transfer to any acceptor other than water. Using ³²PP_i in a variety of conditions, several types of assays failed to detect formation of a phosphorylated enzyme intermediate in the reaction. The results are interpreted as favoring a concerted mechanism for this enzyme.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?