A second NAD-dependent valine dehydrogenase (VDH) of Streptomyces fradiae was detected and purified to homogeneity by affinity chromatography on Reactive-Blue 2 Sepharose followed by gel filtration and Mono Q fast protein liquid chromatography. The relative molecular masses of the native enzyme and its subunits were determined to be 80,000 and 41,000, respectively, indicating that the enzyme is...

It is now believed that the amino groups of isoleucine and valine are accepted by their respective carbon chains during biosynthesis via a transamination. Most of the evidence for this hypothesis has been derived from experiments on isoleucineless and valineless mutants of Escherichia coli and Neurospora crassu (l-4). It is not positively established whether this transamination step can be medi...

Human ectocervical explant cultures were grown in medium with D-valine substituted for L-valine. Pure epithelial cell monolayers were obtained with both dialyzed and undialyzed fetal calf serum. Epithelial cell explant colonies grown in D-valine medium supplemented with undialyzed serum could routinely be subcultured if plated at a density of 1.5 x 10(4) cells/sq cm or higher. Such cultures cou...

when complexed with GTP binds any aminoacyl-tRNA formed and prevents its hydrolysis (Leder, 1973). An average of 0.97mol of tRNAIIe was charged per mol of ATP added to the reaction mix. It may be calculated from the relative reactivity of the isoleucyl-tRNA synthetase towards valine and isoleucine in the presence of tRNA and ATP (Fersht, 1977) and the relative concentrations of valine and isole...

We have developed an HPLC method for measuring carbamylated hemoglobin (CarHb), based on the quantification of valine hydantoin formed from the released NH2-terminal carbamyl valine residue after acid hydrolysis of hemoglobin. In uremia, CarHb is produced by nonenzymatic post-translational modification of the terminal amino group of hemoglobin monomers by isocyanic acid, derived from the sponta...