Figure 3.

In Vivo Production of Cholesterol or Campesterol in Yeast Cells Transformed with SSRs.

(A) Reduction of sterol side chains by SSRs from potato and tomato to produce cholesterol (II) or campesterol (IV) in yeasts producing desmosterol (I) or 24-methylencholesterol (III), respectively. Red arrows indicate reduction steps mediated by SSR2. Blue arrows indicate reduction steps mediated by SSR1. The open black arrow indicates a Δ²⁴-methylation step mediated by SMT.

(B) and (C) Analysis of the extracts of SSR-expressing yeast cells by GC-MS (total ion chromatograms). SSRs from potato and tomato were functionally expressed in desmosterol-producing yeast (B) and 24-methylenecholesterol-producing yeast (C). EV, empty vector control. Peak labels refer to (A).