... between mesophilic and thermophilic phosphoribosyl diphosphate synthaseBjarne Hove-Jensen1 and James N. McGuire21Department of Biological Chemistry and 2Center for Enzyme Research, Institute of ... b,c-diphosphoryl group of ATP to ribose5-phosphate (Rib5P) to produce PRibPP and 5¢-AMP [6,7](Scheme 1 ). The r eaction proceeds by a ttack of the b-phosphate by O-1 of Rib5P [7,8]. PRibPP ... acid sequencing by automated Edmandegradation was performed by the Department of ProteinChemistry, Institute of Molecular Biology, University of Copenhagen, Denmark.Assay of PRibPPsynthase...