An enzyme system from cell-free yeast homogenates mediating the
transfer of the methyl group from S-adenosylmethionine-methyl-C¹⁴
or methionine-methyl-C¹⁴ to C-28 of ergosterol has been studied.
The effects of divalent cations, suithydryl inhibitors and reducing
substances on the activity of the enzyme system have been investigated.
It was established that for...
An attempt has been made to elucidate the biosynthetic precursor
of ethylene in the mold P. digitatum. By application of basic
radiotracer methodology and the utilization of several specifically
labeled radiochemical substrates, it has been possible to demonstrate
that the internal carbon atoms of C-4 dicarboxylic acids such
as succinate,...
The terminal reactions in the biosynthetic pathway of methionine
in Saccharomyces cerevisiae were investigated in this study. Analyses
of a number of methionine auxotrophs for biochemical deficiences
established four mutant groups. It was observed from qualitative feeding
experiments that some auxotrophs were able to utilize S-adenosylmethionine
(AM) and S-adenosyl-homocysteine (AH)...
Aseptic radiorespirometry has been used to examine
the utilization of external carbon sources by proliferating
Thiobacillus thioparus cells. These studies reveal
that glucose, galactose, mannose, fructose, ribose, DL-glutamate,
and L-aspartate were not utilized by this
chemoautotrophic organism. However, it has been shown
that trace amounts of acetate, glycine, DL-serine, DL-alanine,...
The mechanism of transsulfuration and the role of cystathionine
in the biosynthesis of methionine in yeast were investigated.
Saccharomyces were shown to accumulate cystathionine by use
of the ³⁵S labeled compound.
Cell-free extracts of the wildtype clone as well as methionine
auxotrophs were shown to cleave cystathionine. The enzymatically
produced...
Studies were carried out to elucidate the mechanism of enzymatic
control of methionine biosynthesis in Saccharomyces cerevisiae.
Enzymatic studies demonstrated that, in addition to the methionine
activating enzyme, the S-adenosylmethionine:homocysteine
transmethylase enzyme was induced during cultivation in the presence
of excess methionine. A similar, though reduced effect was
observed when...
An enzyme system was prepared from Saccharomyces cerevisiae,
strain MCC, which carries out the transfer of the methyl group from
S-adenosylmethionine or methionine to the side chain of yeast sterols.
The cell-free system has been shown to be incapable of synthesizing
ergosterol but carries out the synthesis of two as...