Leucyl transfer ribonucleic acid synthetase (EC 6.1.1.4, L-leucine: tRNA ligase (AMP)) has been purified from Escherichia coli and is free of other aminoacyl-tRNA synthetases, tRNA-methylating enzymes, and CpCpA-adding enzymes. Several criteria suggest that there is one synthetase with specikity for two forms of leucine-specik tRNA which can be separated by countercurrent distribution: purifica...

We describe a simple method for enzymatic synthesis of L and D amino acids from a-keto acids with Escherichia coli cells which express heterologous genes. L-amino acids were produced with thermostable L-amino acid dehydrogenase and formate dehydrogenase (FDH) from a-keto acids and ammonium formate with only an intracellular pool of NAD for the regeneration of NADH. We constructed plasmids conta...

Two trials were conducted to estimate the leucine requirement of sows during a 21-day lactation. In trial 1, hominy feed, geletin, corn sugar, vitamins, minerals and indispensable amino acids were used to formulate a diet containing adequate levels of all essential nutrients except leucine. L-leucine was added to this mixture to produce five diets containing: .44 (basal), .64, .84, 1.04 and 1.2...

OBJECTIVES Changes in the activity of alanine aminopeptidase, leucine aminopeptidase and cathepsins D and L in the liver and kidney of male and female of mice, injected with 0.4 IU/kg b.w. insulin for 4 and 8 days. METHODS The homogenates of the liver and kidney were taken for examination. The activity of alanine aminopeptidase, leucine aminopeptidase and cathepsins D and L has been determine...

A novel method was developed for the diagnosis of maple syrup urine disease (MSUD) by the determination of L-valine, L-leucine, L-isoleucine and L-phenylalanine in dried blood spots of newborns by gas chromatography-mass spectrometry (GC-MS). The four amino acids were extracted from blood samples by methanol and derivatized by n-butanol and trifluroacetic anhydride under optimum reaction condit...

All cells in the intestinal villus of the rat are capable of synthesizing protein from amino acid precursors (l-leucine). Moreover, polyribosomes from both crypts and villi are equally able to incorporate l-leucine into protein. Unlike other tissues, e.g. liver, there is no diurnal variation of protein synthesis in the intestine of the unfed rat, whether leucine is administered intraluminally o...

Bitespiramycin, a group of 4"-O-acylated spiramycins with 4"-O-isovalerylspiramycins as the major components, was produced by recombinant spiramycin-producing strain Streptomyces spiramyceticus harboring a 4"-O-acyltransferase gene. The experiment was initially performed in synthetic medium with 0.5 g l(-1) Valine, Isoleucine or Leucine feeding at 36 h cultivation. When valine was fed, the biol...

We describe a simple method for enzymatic synthesis of L and D amino acids from alpha-keto acids with Escherichia coli cells which express heterologous genes. L-amino acids were produced with thermostable L-amino acid dehydrogenase and formate dehydrogenase (FDH) from alpha-keto acids and ammonium formate with only an intracellular pool of NAD+ for the regeneration of NADH. We constructed plasm...