Isamu Sano

Hypusine, a new amino acid occurring in bovine brain: Isolation and structural determination

Abstract A new basic amino acid, hypusine, was isolated from the homogenate of bovine brain tissue by ion-exchange column chromatography. The structure of this amino acid was determined to be N 6 -4-amino-2-hydroxybutyl)-2,6-diaminohexanoic acid on the basis of its physical properties involving NMR and mass spectra, as well as chemical degradation including periodate oxidation and reduction with HI and P.

IDENTIFICATION OF N‐ACETYL‐α‐ASPARTYLGLUTAMIC ACID IN THE BOVINE BRAIN

CURATOLO, DARCANGELO, LINO and BRANCATI (1965) have reported the occurrence in the rabbit brain of a compound tentatively identified by them as N-acetylaspartylglutamic acid. The identification of the compound was based on the facts that (a) a fraction of the brain extract separated by ion exchange chromatography contained a ninhydrin-negative compound which could be hydrolysed to give aspartic and glutamic acids and (b) mild acid hydrolysis of the fraction resulted in the release of N-acetylaspartic and glutamic acids. They have not determined whether the compound is N-acetyl-aor p-aspartylglutamic acid or presented definite evidence that the acyl group covering the amino group of the aspartic residue is an acetyl group. Further, the synthesis of the authentic compound is required for the final identification. This paper describes the purification of N-acetylaspartyl glutamic acid obtained from bovine brain and the identification of the compound by synthesis. The distribution of the compound was examined in various tissues of the rabbit, guinea pig and rat: it was found that the compound was detected only in the brain.

β-Aminoisobutyrate-α-ketoglutarate transaminase in relation to β-aminoisobutyric aciduria

Abstract β-Aminoisobutyrate-α-ketoglutarate transaminase described by Kupiecki and Coon was further purified from hog kidney. The enzyme catalyzed the transamination with its l isomer while the d isomer, the natural form, was practically inactive as the substrate. The activity of the enzyme in the kidney of an hereditary high excretor of β-aminoisobutyric acid was not different from the activities of the low excretors. These findings indicate that the enzyme is not the principle enzyme catalyzing the degradation of the amino acid in vivo, and suggest the occurrence of another enzyme reaction by which d -β-aminoisobutyric acid is metabolized.

Isolation of γ-l-glutamyl-l-glutamic acid and γ-l-glutamyl-l-glutamine from bovine brain

Abstract Two peptides have been isolated from 28.5 kg of bovine brains using a combination of ion-exchange chromatographic separations. They were identified as γ- l -glutamyl- l -glutamic acid and γ- l -glutamyl- l -glutamine. The synthesis of these peptides has been described.

Identification of γ-glutamylserine, γ-glutamylalanine, γ-glutamylvaline and S-methylglutathione of bovine brain

Abstract Three γ-glutamyl dipeptides and a γ-glutamyl tripeptide were purified from bovine brain by a combination of ion-exchange chromatogaphic techniques. These were identified as γ-glutamylserine, γ-glutamylalanine, γ-glutamylvaline and S -methylglutathione by acid hydrolysis, terminal amino acid determination and comparison of paper chromatographic and paper electrophoretic properties of the isolated compounds with those of synthetized peptides.

A METHOD OF DETERMINATION OF HOMOCARNOSINE AND ITS DISTRIBUTION IN MAMMALIAN TISSUES

HOMOCARNOSINE, y-aminobutyryl-L-histidine, which was isolated by PISANO, WILSON, COHEN, ABRAHAM and UDENFRIEND (1961), and later by KANAZAWA, KAKIMOTO, MIYAMOTO and SANO (1965), occurs in the central nervous system. ABRAHAM, PISANO and UDENFRIEND (1962) found this dipeptide in a higher concentration in the white matter of human brains. In our preliminary experiment (SHIMIZU, KAKIMOTO and SANO, 1966), however, the concentration of homocarnosine was higher in the thalamus, hypothalamus and cerebellum than the cerebral cortex, and the difference in the concentration between the grey and white matter was not clear in the human brain. This led us to re-examine the concentration of homocarnosine in various regions of the human brain as well as in the brains of different species of vertebrates. M E T H O D S

Simple peptides in brain.

Publisher Summary Although polypeptides such as substance P and related compounds, neurohypophyseal hormones, and the releasing factors of the anterior hypothalamus have been the subjects of extensive studies in the past decade, relatively few studies have been made of the occurrence of smaller oligopeptides in the brain and of their possible function. Automatic amino acid analysis of protein-free extracts of mammalian brain demonstrated the presence of unknown ninhydrin-positive compounds, which disappeared after acid hydrolysis. The nomenclature of the di- and tripeptides is ambiguous. Their classification as di- or tripeptides as a group may be justified because naturally occurring peptides can be separated grossly into three classes: (1) di- or tripeptides, (2) biologically active peptides having 7-15 amino acid residues, which include most peptide hormones and antibiotics, and (3) the larger polypeptides, which have very diverse biological functions. This chapter describes the occurrence, distribution, and metabolism of oligopeptides, which are found in the mammalian brain up to the present time. The physiological and pharmacological actions of some of them and of compounds related to them also arediscussed, although unfortunately there is almost nothing known about this.

α-(γ-AMINOBUTYRYL)-LYSINE IN MAMMALIAN BRAIN: ITS IDENTIFICATION AND DISTRIBUTION

Abstract— α‐(γ‐Aminobutyryi)‐lysine was identified in rabbit brain. This compound was detected exclusively in the brain of mammals, but not in other tissues. It is not concentrated in any particular region of the rabbit brain.

Isolation and identification of γ-l-glutamylglycine from bovine brain

A peptide has been isolated from 28.5 kg of bovine brains through ion-exchange chromatography, and identified as γ-l-glutamylglycine. The identification was based on elementary analysis, determination of amino acid sequence, infrared spectrum, paper chromatography, paper electrophoresis and determination of configuration of glutamyl residue by l-glutamic acid decarboxylase (EC 4.1.1.15). The synthesis of α- and γ-l-glutamylglycine are also described.

A method of determination of cystathionine and its distribution in human brain.

CYSTATHIONINE occurs at a high concentration in human and monkey brain but at a low level in the brains of other vertebrates and in organs other than brain (TALLAN, MOORE and STEIN, 1958; OKUMURA, OTSUKI and KAMEYAMA, 1960). However, the cystathionine concentration of human brain reported was not consistently high. OKUMURA et ul. (1960) determined the concentration of cystathionine in various biopsy and autopsy samples of human brains, and suggested that ante mortem metabolic conditions andlorpost mortem processes might cause a variation in the concentration, whilst other investigators (TALLAN et al., 1958; GERRITSEN and WAISMAN, 1964; BRENTON, CUSWORTH and GAULL, 1965) have shown smaller variations on autopsy specimens. The factors governing the concentration in human brain remained to be elucidated (TALLAN, 1962). Detailed information about the distribution of cystathionine in human brain is not available at present; more especially, the differences in concentration in the grey and the white matter of human brain has not been reported, and this may be the cause of the discrepancy between the previous data. The determination of cystathionine in animal tissues has depended on the separation of the amino acid by ion exchange chromatography according to the modified method of MOORE and STEIN (1954), followed by the ninhydrin reaction; but this method is not suitable for the treatment of large numbers of samples. We have recently devised a new method of quantitative estimalion of cystathionine in animal tissues. Using this method, the post mortem changes and the distribution of cystathionine have been studied in the human brain.