NON-OXIDATIVE CYCLIZATION OF SQUALENE BY TETRAHYMENA-PYRIFORMIS - INCORPORATION OF A 3-BETA-HYDROGEN (DEUTERIUM) ATOM INTO TETRAHYMANOL

3α- and 3β-[2H1]-5α-cholestanes and 3α- and 3β-[2H1]-4>4-dimethyl-5a-cholestanes were synthesized, and their 2HNMR spectra were determined. The chemical shifts of the 3α- and 3β-dcuterio isomers were separated by 0.46 ppm in the cho-lestane isomers and by 0.23 ppm in the 4, 4-dimethylcholestanes. The results were then used to establish that the nonoxidativecyclization of squalene by enzymes of Tetrahymena pyriformis in D2O proceeds with the introduction of a 3β-deuterium atom into tetrahymanol. The 2H NMR results were supported by comparison of the C-2H stretching patterns of 3α- and 3β-[2H1]-4, 4-dimethyl-5α-cholestanes with the C-2H stretching pattern of biosynthetic tetrahymanol. The mechanism of the nonoxidative cyclization of squalene is also discussed.© 1979, American Chemical Society. All rights reserved.