The presence of free D-serine,D-alanine and D-proline in human plasma

Twelve neutral free amino acids, i. e., serine, threonine, glutamine, asparagine, alanine, proline, methionine, tyrosine, valine, leucine, isoleucine and phenylalanine, were surveyed for the presence of D-enantiomers in plasma samples from patients with renal diseases and from normal subjects. D-serine, D-alanine and D-proline were found in the patient's plasma. The highest concentrations (D/L ratio) of D-serine, D-alanine and D-proline were 0.2362, 0.2087 and 0.0986, respectively. The sum of the contents of the three D-amino acids in a plasma sample correlated with the serum creatinine level of the subject. No D-amino acid was shown to be present in the plasma proteins.     

D-Amino acids in mouse tissues are not of microbial origin

Summary Neutral free D-amino acid contents in the serum, kidney, liver, brain, small intestine and urine in germ-free mice and those in specific pathogen-free mice were compared. No significant difference was found. This strongly suggests that the free D-amino acids which were shown to be present in mice in our previous work^{1, 2} did not originate from the enteric microbial flora.     

D-amino acids in mouse tissues are not of microbial origin

Neutral free D-amino acid contents in the serum, kidney, liver, brain, small intestine and urine in germ-free mice and those in specific pathogen-free mice were compared. No significant difference was found. This strongly suggests that the free D-amino acids which were shown to be present in mice in our previous work did not originate from the enteric microbial flora.     

In vitro conversion of sepiapterin to isosepiapterin via dihydrobiopterin

Résumé La dihydrobioptérine obtenue par le mélange réactionel de sépiaptérine et de sa réductase se transforme en substance jaune par traitement à l'acide sulfurique. Employant des techniques chromatographiques, l'analyse du spectre d'absorption UV et l'analyse chimique, on a pu mettre en évidence que cette substance est identique de l'isosépiaptérine.     

The presence of free D-amino acids in mouse tissues

The presence of free D-amino acids in mouse kidney, liver, brain, heart, lung, thymus and serum has been shown with an enzymic microdetermination method. The D-amino acid levels were higher in the extracts of kidney and liver than in those from other organs.     

Farnesylated gamma-subunit of photoreceptor G protein indispensable for GTP-binding

Transducin, composed of subunits T alpha, T beta and T gamma, is a member of a heterotrimeric G-protein family, and transduces the light signal in visual cells. We have recently found that bovine T beta gamma can be separated into two components. T beta gamma-1 and T beta gamma-2, each of which has its own gamma-subunit, T gamma-1 and T gamma-2, respectively. T beta gamma-2 enhances the binding of GTP to T alpha in the presence of metarhodopsin II by about 30-fold compared with T beta gamma-1. Here we show that a farnesyl moiety is attached to a sulphur atom of the C-terminal cysteine of T gamma-2 (active form), a part of which is additionally methyl-esterified at the alpha-carboxyl group. In T gamma-1 (inactive form), however, such modifications are missing. Thus, the farnesyl moiety attached to the gamma-subunit is indispensable for the GTP-binding activity of transducin. This suggests that a similar modification may occur in the gamma-subunits of other heterotrimeric G proteins involved in biological signal transduction processes.     

The presence of free D-amino acids in mouse tissues

Summary The presence of free D-amino acids in mouse kidney, liver, brain, heart, lung, thymus and serum has been shown with an enzymic microdetermination method. The D-amino acid levels were higher in the extracts of kidney and liver than in those from other organs.     

On the presence of sepiapterin reductase different from folate and dihydrofolate reductase in chicken liver

Résumé Nous avons démontré dans le foie de poussin l'existence d'un ferment qui réduit spécifiquement la sépiaptérine. Il est capable de séparer le ferment de réductase d'acide folique et d'acide dihydrofolique après précipitation fractionnaire de sulfate d'ammonium. Le ferment, réductase de sépiaptérine, se trouve largement dans les foies des mammifères, tels que rat, cochon, lapin, cheval et boeuf.