Plant Sterol Methyltransferases: Phytosterolomic Analysis, Enzymology, and Bioengineering Strategies

So far as is known, the biosynthesis of phytosterols is a ubiquitous property of plants and microbes, whereas insects fail to synthesize the sterol nucleus. All of them require phytosterols to grow and mature. In recent years, the availability of stable isotopes, modern instrumentation such as high-field nuclear magnetic resonance spectroscopy and molecular biology have offered new insights into the evolutionary development of sterol structure-enzyme function relationships, pathway sequencing, chemical ecology, and in the case of bioengineering provides a mechanism to generate value-added traits. Here we describe results obtained with these techniques in relation to the critical enzyme that controls the pattern of C-24 side-chain diversity, the (S)-adenosyl-L-methionine: Δ²⁴-sterol methyltransferase (SMT).