The biosynthesis of C55 polyprenols by a cell-free preparation of Lactobacillus plantarum

Abstract

A cell-free supernatant of lysates of Lactobacillus plantarum catalyses the synthesis of lipids from [2-14C]mevalonate. Of the added mevalonate, 7.5% is incorporated into lipids, which were fractionated into five components. About 4% of the radioactivity in these lipids co-chromatographs with compounds shown by mass spectrometry, n.m.r. and i.r. spectroscopy to be C55 polyprenols, and about 2% co-chromatographs with a hexamer. The rest of the radioactivity is in more complex fractions. Analysis by mass spectrometry, n.m.r. and i.r. spectroscopy shows that the major C55 polyprenol is undecaprenol, accompanied by an isomer containing one reduced isoprene unit. A Kuhn–Roth degradation of [14C]polyprenols indicates that the supernatant catalyses synthesis of these compounds de novo.