CHARACTERIZATION OF UNDECAPRENOL KINASE FROM LACTOBACILLUS-PLANTARUM

A membrane-bound undecaprenol kinase from Lactobacillus has been identified by observing the ATP-dependent phosphorylation of [14C] undecaprenol. The product of this reaction was shown to be [14C]undecaprenyl monophosphate by comparison of its chromatographic mobilities with authentic undecaprenyl monophosphate. It was also shown that 32P from [γ-32P]ATP was incorporated into undecaprenyl monophosphate. The kinase was partially solubilized by a variety of methods utilizing Triton X-100. Both the membraneassociated and solubilized enzymes required Mg2+, Triton X-100 and dimethylsulfoxide for activity. The enzyme preferentially phosphorylated the C45, C50 and C55 polyprenols. Geranylgeraniol (C20) and dolichol (C100), however, were utilized only 6% and 13% as well as undecaprenol, respectively. Despite the 8-fold difference in apparent V values, the apparent Km values for dolichol and undecaprenol were both 14 μM. The apparent Km for the nucleotide cosubstrate, ATP, was 2 mM. No other nucleoside triphospliate could substitute for ATP. © 1979.