In the course of testing the possible coenzymic function of the phosphorylated vitamin B, derivatives on the synthesis of glucosamine 6-phosphate by a rat liver preparation, the appearance of a yellow color similar to that of pyridoxal 5-phosphate was observed in the samples containing pyridoxamine 5-phosphate. Further investigation has revealed the presence of a soluble enzyme system in extrac...

Two Bacillus subtilis genes encoding two proteins (currently annotated ThiD and YjbV) were overexpressed and characterized. YjbV has 4-amino-5-hydroxymethyl-2-methylpyrimidine and 4-amino-5-hydroxymethyl-2-methylpyrimidine pyrophosphate kinase activity and should be reannotated ThiD, and B. subtilis ThiD has pyridoxine, pyridoxal, and pyridoxamine kinase activity and should be reannotated PdxK.

As part of a study of the regulation of aspartate aminotransferase isozymes (EC 2.6.1. l), we have investigated the characteristics of inhibition of the anionic and cationic isozymes by u-erythrose 4-phosphate and glycolaldehyde phosphate, the naturally occurring homologues of D-glyceraldehyde 3-phosphate. Erythrose-4-P has been found to be a time-dependent inhibitor of both the cationic and an...

Pig heart “soluble” glutamic-aspartic transaminase (L-aspartate : 2-oxoglutarate aminotransferase, EC 2.6.1.1) will catalyze the exchange of an amino group between glutamate and ketoglutarate without the participation of any other amino acid or keto acid (1). This “exchange transamination” also occurs between aspartate and oxaloacetate. The rates of these reactions are comparable to the physiol...

The amino group carrier function of the coenzyme of transamination was postulated on the basis of coenzyme properties and model experiments (1, 2) and was established for the enzymatic reaction by the observation that pyridoxal and pyridoxamine phosphates exhibit equivalent activity in the reactivation of crude apoglutamate oxaloacetate transaminase (3) and by direct spectrophotometric observat...

The inhibition of ribonuclease Bi by 3'-N-hydroxyurea-3'-deoxythymidine 5'-phosphate is enhanced by 30-fold in the presence of Zn(2+). Thus, an N-hydroxyurea nucleotide can recruit Zn(2+) to inhibit the enzymatic activity of a ribonuclease. This result engenders a general strategy for the inhibition of non-metalloenzymes by metal complexes.

Active transport of pyridoxine, pyridoxal, and pyridoxamine occurs in resting cells of Saccharomyces carlsbergensis 4228 and can lead to intracellular concentrations of free vitamin much higher than those supplied externally. The initial Km for pyridoxine uptake is 3.6 x 10(-7) M at 30 degrees and pH 4.5, which are optimum for growth. Transport is inhibited by many unphosphorylated vitamin anal...

BACKGROUND/AIMS Pyridoxamine dihydrochloride (Pyridorin™) blocks pathogenic oxidative pathways in the progression of diabetic nephropathy. The pyridoxamine pilot study was designed to test entry criteria and outcomes. Subjects had SCr 1.3-3.5 mg/dl, protein-to-creatinine ≥1,200 mg/g and used a surrogate outcome of ΔSCr over 52 weeks. Subjects had to be on a maximally tolerated dose of ACE/ARB f...