Uptake and metabolism of L-alanine by freshly isolated trout hepatocytes has been analyzed. This amino acid is incorporated 'uphill' by different carriers, either Na-dependent or Na-independent. Na-dependent uptake shows the characteristics of an ASC system on the basis of cation dependence and substrate preferences. The Na-independent uptake is split between an L-cysteine-sensitive system and ...

Lactobacillus casei grows in the absence of vitamin Ba, provided that D-alanine and an unidentified peptide are added to a medium complete in other nutrients (1, 2). A partial hydrolysate of protein contained several chromatographically distinct fractions that possessed this “peptide factor” activity (3). It appeared likely that a single amino acid linked in a variety of combinations was respon...

Germination of spores of the genus Bacillus can be stimulated by heat, L-alanine, or manganese. The reversal of L-alanine stimulation by D-alanine (Hills, 1950) appears to be specific and, in the present study, affords a tool for the exploration of the mechanisms and interrelations among heat, manganese and L-alanine stimulations. The heat stimulation of bacterial spore germination has long bee...

UDP-N-acetylmuramic acid:L-alanine ligase that is encoded by the murC gene, is indispensable for bacterial peptidoglycan biosynthesis and an important target for the development of antibacterial agents. Structure of MurC ligase with substrates has been described, however, little validation via studying the effects of mutations on the structure of MurC has been performed. In this study, we carri...

Cell wall-membrane preparations of Escherichia coli, prepared by the ethylenediaminetetraacetic acid-lysozyme method, contain enzymes which catalyze the oxidation of d-alanine and, to a lesser extent, l-alanine into pyruvate and ammonia without the formation of hydrogen peroxide. The kinetic parameters were (i) pH optima of 8.3 to 8.4 for l- and d-alanine and (ii) a K(m) value of 6.6 +/- 0.2 mM...

Profound alterations in host metabolism in lung cancer patients with weight loss have been reported, including elevated phosphomonoesters (PMEs) as detected by 31P magnetic resonance spectroscopy (MRS). In healthy subjects, infusion of L-alanine induced significant increases in hepatic PMEs and phosphodiesters (PDEs) due to rising concentrations of 3-phosphoglycerate and phosphoenolpyruvate, re...

In the peptidoglycan of Mycobacterium leprae, L-alanine of the side chain is replaced by glycine. When expressed in Escherichia coli, MurC (UDP-N-acetyl-muramate:L-alanine ligase) of M. leprae showed K(m) and V(max) for L-alanine and glycine similar to those of Mycobacterium tuberculosis MurC, suggesting that another explanation should be sought for the presence of glycine.