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)...
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...
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,...
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...
Early studies on the biosynthesis of Sarubicin A, 1, had suggested the
intermediacy of the novel aromatic amino acid 6-hydroxyanthranilic acid,
17. To investigate the biosynthetic steps beyond 17, [¹³C-¹⁵N carboxamide]
6-hydroxyanthranilamide, 27a, was synthesized, and fed to fermentations
of Streptomyces helicus. Incorporation of 27a into 1 provided suggestive
evidence...