Lactobacillus plantarum undecaprenyl pyrophosphate synthetase: Purification and reaction requirements

Abstract

Undecaprenyl pyrophosphate synthetase was partially purified from Lactobacillus plantarum by DEAE-cellulose, hydroxyapatite, and Sephadex G-100 chromatography in Triton X-100. The enzyme has a molecular weight between 53,000 and 60,000. The enzyme demonstrated a fivefold preference for farnesyl pyrophosphate rather than geranyl pyrophosphate as the allylic cosubstrate, whereas dimethylallyl pyrophosphate was not effective as a substrate. Polyprenyl pyrophosphates obtained using either farnesyl or geranyl pyrophosphate as cosubstrate were chromatographically identical. Hydrolysis of these polyprenyl pyrophosphates with either a yeast or liver phosphatase preparation yielded undecaprenol as the major product. Incorporation of radioactive label from mixtures of Δ 3-[1- 14C]isopentenyl pyrophosphate and Δ 3-2R-[2- 3H]isopentenyl pyrophosphate into enzymic product indicated that each isoprene unit added to the allylic pyrophosphate substrate has a cis configuration about the newly formed double bond. The removal of detergent from enzyme solutions resulted in a parallel loss in enzyme activity when analyzed with either farnesyl or geranyl pyrophosphate as cosubstrates. Enzymic activity was restored on addition of Triton X-100 or deoxycholate. The enzyme exhibited a pH-activity profile with optima at pH 7.5 and 10.2. It also demonstrated a divalent cation requirement, with Mg 2+, Mn 2+, Zn 2+, and Co 2+ exhibiting comparable activities.