Salmonella typhimurium possesses a permease specific for L-methionine (K, of 0.1 to 0-2 p ~ ) . Competition studies have shown that the permease has little or no affinity for the other L-amino acids commonly found in proteins. Methionine uptake was competitively inhibited by the growth inhj bitory analogues DLethionine, a-methyl-DL-methionine and DL-methionhe-DL-sulphoximine. Mutants resistant ...

It has been indicated lately that higher plasma homocysteine is one of the risk factors in neural tube defects(NTDs) and vascular disease. Methionine synthase is a key enzyme in homocysteine metabolism. The defects of methionine synthase activity could result in hyperhomocysteinemia and methionine auxotrophy. The gene mutations of methionine synthase with the epidemiological studies of NTDs are...

1. Glycylsarcosine, a peptide which is slowly hydrolysed by the intestine, is transported into the jejunal mucosal cells of the hamster by an active Na+-dependent process. 2. Uptake of glycylsarcosine is inhibited by L-methionyl-L-methionine but not by L-methionine, suggesting that L-methionyl-L-methionine and glycylsarcosine share an uptake mechanism which is independent of that for free methi...

The previously reported inability of methionine to stimulate cephalosporin C production in a cysteine auxotroph is due to cysteine interference with methionine uptake. In such a cse, "illicit transport" of alanylmethionine can be used to demonstrate the efficacy of methionine in such mutants blocked in the path from methionine to cysteine. This result supports the hypothesis that the stimulator...

the objective of this study was to assess the adsorption potential of activated carbon (ac) asan adsorbent for the removal of murexide (mu) from aqueous solutions. the influence of variablesparameters including ph, amount of adsorbent, sieve size of adsorbent, temperature and contact timeon mu removal was studied. following optimization of variables, the relation between concentrations ofdye re...

a total of 160 day-old male broiler chickens (ross 308) were divided in a completely randomized design experiment, and assigned to 8 treatments and 4 replicates in their experimental units (cages). treatments included: t1: basal diet with no additional methionine, t2: basal diet plus 0.06, t3: basal diet plus 0.11, t4: basal diet plus 0.17 % of dl-methionine, t5: basal diet plus 0.06, t6: basal...

this experiment was conducted in international researchery institute of sturgeon fishes shahid  dadman. the basal diet contained fish meal as protein source (cp=40%). five diets were supplemented with 5 graded levels of methionine, (0, 0.5,1 ,1.5, 2% met per kg diet) . each diet was randomly assigned to triplicate groups of 195 juvenile huso huso (initial weight 31.9± 2.8) in fiftin 500-l circu...

In immature rib segments prepared from morning-glory (Ipomoea tricolor) flower buds, the major soluble metabolite formed from tracer amounts of l-methionine-U-(14)C was S-methylmethionine (SMM). In segments of senescing ribs, (14)C was progressively lost from SMM and appeared in free methionine. Immature segments contained about 4 nmoles of free methionine and about 16 nmoles of SMM per 30 segm...

Extensive research on the formation of methionine has implicated vitamin B12 as a cofactor in the final reaction of the biosynthetic sequence. Since plants and fungi do not produce or require B12, an alternate reaction must also exist. It is thus not surprising that Escherichia coli has been found to possess two mechanisms for the methylation of homocysteine to methionine (9). These reactions a...