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Researcher's Work Appears in Two Publications

One of BTR's senior research scientists, Dr. Linsheng Song, has written two papers related to research conducted on BTR's isoprenoid technology. One article, which was published recently in Analytical and Bioanalytical Chemistry, details a new way to assay mevalonate kinase. Another article appearing in Applied Biochemistry and Biotechnology focuses on the purification of a soluble phosphatase related to the production of farnesol. Abstracts from both articles follow:

Reduction of Background Interference in the Spectrophotometric Assay of Mevalonate Kinase.
Analytical and Bioanalytical Chemistry. 2006. 384(6):1444-1445

Mevalonate kinase can be conveniently assayed by coupling to two other reactions and monitoring the consumption of NADH optically at 340 nm. No mevalonate kinase was detected in crude extracts of Saccharomyces cerevisiae strains, however, because of background interference measured in the absence of mevalonate. A strain of S. cerevisiae over-expressing mevalonate kinase was used to establish conditions for reduction of background interference. This method has been successfully applied to S. cerevisiae strains containing a wild type level of mevalonate kinase.

A Soluble Form of Phosphatase in Saccharomyces cerevisiae Capable of Converting Farnesyl Diphosphate to E,E-Farnesol.
Applied Biochemistry and Biotechnology. 2006. 128(2):149-158

After anion exchange chromatography, the soluble fraction of a cell-free extract of Saccharomyces cerevisiae showed two phosphatase activity peaks when p-nitrophenyl phosphate (pNPP) was used as the substrate. However, only the second pNPP active peak demonstrated the ability to convert farnesyl diphosphate (FPP) to E,E-farnesol. N-terminal sequence analysis of the purified pNPP/FPP phosphatase revealed that it was a truncated form of alkaline phosphatase Pho8 lacking 62 amino acids from the N-terminus and was designated Pho8Δ62. Although other isoprenyl diphosphates such as geranyl diphosphate (GPP) and geranylgeranyl diphosphate (GGPP) could also be hydrolyzed by Pho8Δ62 to the corresponding alcohols, selectivity was observed among these substrates. The optimum pH was 7 for all three isoprenyl diphosphate substrates. Although lower hydrolytic activity was observed for FPP and GGPP at pH 6 and 8.5, hydrolysis of GPP was only observed at pH 7. Mg²⁺ and Mn²⁺ inhibited hydrolysis of FPP and GGPP, and GGPP was more sensitive to Mg²⁺ inhibition than FPP. The rate of FPP hydrolysis increased in the presence of Triton X-100.

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