The Purification and Properties of Pig Liver Geranyl Pyrophosphate Synthetase

Biosynthesis of sesquiterpenes

“…In order to investigate the mode of cyclization of the farnesyl chain, [1-3H2]-and [2-3H]farnesyl pyrophosphates (2) (each used in admixture with [2-14C]-2) were used as precursors of (6) retained two tritium atoms (in agreement with Hanson's work259) upon incorporation into trichothecolone (104). The radioactive trichothecolone (104) was then degraded by a series of steps in which the carbon atom at C-8 was specifically removed.…”

“…The retention of four tritium labels into trichothecolone after feeding [2-3H2] mevalonate (6) is an unexpected result.261•263 One label was demonstrated by oxidation to be at C-4. The location of one of the other labels was suggested after the multiply labeled 107 (obtained from [2R-3H]-6) lost only one tritium upon incorporation into trichothecolone (104) and trichothecin (92). A tritium must therefore have migrated from C-8 to C-7 during formation of 92, possibly via an NIH shift type mechanism on the epoxide 108.…”

Purification and characterization of two forms of geranyl transferase from Ricinus communis

“…Geranyl transferases derived from mammalian systems have somewhat different properties from geranyl transferases I and II reported here. Pork liver geranyl transferase has been reported to have a pH optimum of 7.8-8.0 (Dorsey et al, 1966;Holloway and Popjak, 1967) as opposed to an optimum of 6.8-7.0 for castor bean transferase. Differences in the effect of sulfhydryl inhibitors on these enzymes are in general quite striking.…”

“…Differences in the effect of sulfhydryl inhibitors on these enzymes are in general quite striking. Dorsey et al (1966) reported 97-98% inhibition upon preincubation of pork liver enzyme in 1 µ /7-hydroxymercuribenzoate or 1 mM Ar-ethylmaleimide and 37% inhibition in the presence of 10 mM iodoacetamide. Popjak (1969) reported 80% inhibition upon preincubating pork liver transferase with 0.5 µ /t-hydroxymercuribenzoate, 5 µ A-ethylmaleimide, or 2 mM iodoacetamide.…”

“…23,1974 ase activity from crude yeast autolysates which catalyzed condensations between Me2allyl-PP and iPe-PP to yield geranyl-PP, farnesyl-PP, and Ger2PP. Since then prenyl transferases have been detected and partially characterized from a variety of plant, animal, and microbial sources (Kandutsch et al, 1964;Nandi and Porter, 1964;Wells et al, 1964;Benedict et al, 1965;Dorsey et al, 1966;Holloway and Popjak, 1967;Ogura et al, 1972;Momose and Rudney, 1972). Prenyl transferases of longer chain specificity have also been partially purified and studied (Christenson et al, 1969; Kurokawa et al, 1971).…”