Distinctions in Mollicutes Purine Metabolism: Pyrophosphate-Dependent Nucleoside Kinase and Dependence on Guanylate Salvage

Abstract

Cell preparations of Acholeplasma florum L1T, Acholeplasma axanthum S743T, Acholeplasma granularum BTS-39T, Spiroplasma floricola 23-6T, Mycoplasma gallisepticum S6, and Mycoplasma arginini G230T were examined for 13 cytoplasmic enzyme activities involved in the salvage and interconversion of nucleobases, nucleosides, and 5′-mononucleotides. The unique pyrophosphate-dependent nucleoside kinase activity known only in Acholeplasma laidlawii B-PG9 was found in A. axanthum and A. granularum. All the organisms could be divided into three groups based upon their patterns of purine salvage and interconversion activities. All the tested organisms, A. laidlawii, and apparently Mycoplasma mycoides subsp. mycoides lack the ability to synthesize guanylates from other purine mononucleotides, indicating that these members of the class Mollicutes can only salvage guanylates. The plant epiphytes A. florum and S. floricola had an identical purine enzyme pattern which was different from those of all other members of the Mollicutes studied.