Methionine Biosynthesis in Lemna

Methionine methyl group metabolism in lemna.

To provide information upon the ways in which Lemna paucicostata uses the methyl group of methionine, plants were grown for various periods (from 1 minute to 6.8 days) in the presence of a tracer dose of radioactive methyl-labeled methionine. Protein methionine accounted for approximately 19% of the accumulated methyl moieties; other methylated products, about 81%. The latter group included (pe...

Biosynthesis of methionine in liver.

Conversion of 1 carbon precursors to methionine methyl groups in a cell-free preparation was first demonstrated by Berg in this laboratory (2). Berg inactivated a pigeon liver extract by Dowex I-Cltreatment and dialysis and found that it could be activated by a boiled extract of pigeon liver. Methionine methyl formation in dialyzed liver estracts has been activated recently by mixtures of known...

Adaptation of Lemna paucicostata to Sublethal Methionine Deprivation.

During initial exposure to 40 nanomolar propargylglycine (PAG), Lemna paucicostata colonies undergo abnormal fragmentation and a lag in frond emergence, most severe at 24 to 48 hours. Thereafter, frond emergence resumes and the frond/colony ratio rises. Such ;adapted' plants withstand subculture into the same concentration of PAG without fragmentation or decreases in frond emergence, and displa...

The biosynthesis of D-apiose in Lemna minor.

Lemna minor incorporates radioactivity from n-glucose-l14C, D-glucose-2-*4C, D-glucose-3 ,4-r4c, D-glucose-6-14C, sodium acetate-Z-14C, DL-serine-3-14C, and L-methionine-14CH8 into the n-apiose moiety of cell wall polysaccharide. The mechanism of biosynthesis of this hydroxymethyltetrose was studied by determining the distribution of 14C in n-apiose after feeding various labeled precursors. Lab...

Acetylhomoserine and methionine biosynthesis in Neurospora.