Phosphoribosyl Pyrophosphate Degradation in Human Tissues
- 1 December 1974
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Biochemistry
- Vol. 52 (12) , 1162-1166
- https://doi.org/10.1139/o74-161
Abstract
Enzymatic hydrolysis of phosphoribosyl pyrophosphate (PP-ribose-P) in dialyzed human tissue homogenates had a specific activity ranging from 0.15 to 1.37 μmol mg−1 h−1. Our observations on human placenta have characterized this reaction: (1) PP-ribose-P was degraded in the absence of Mg with stoichiometric release of Pi at 37 °C; (2) the reaction occurred from pH 5 to 10.5 with the maximum activity in the alkaline range; (3) PP-ribose-P degrading activity was localized mainly in the microsomal fraction; (4) alkaline phosphatase rather than 5′-nucleotidase was responsible for the degradation of PP-ribose-P; (5) the Km for PP-ribose-P was 0.3 mM; (6) PP-ribose-P hydrolysis was altered by many phosphorylated compounds, both nucleoside and sugar derivatives, Pi, and PPi in concentrations ranging from 0.1 to 10.0 mM.Keywords
This publication has 0 references indexed in Scilit: