Nosiheptide,a sulfur-containing peptide antibiotic isolated fromStreptomyces actuosus 40037

Summary Nosiheptide (9671 R.P.) isolated fromStreptomyces actuosus 40037 (NRRL 2954) is a sulfur-containing polypeptidic antibiotic, quite different from all the other members of this family. Very active in vitro against gram-positive bacteria, it is inactive in vivo in experimentally infected mice. Not toxic, even at high dose, it may be used as a feed additive for chickens and pigs and it shows a favourable effect on the growth and conversion index.     

The structure of a novel antitumor antibiotic,saframycin A

Summary A structure is assigned to saframycin A, a novel antitumor antibiotic fromStreptomyces lavendulae No. 314, on the basis of¹³C NMR-spectral data.     

Relationship between the structure of chloramphenicol and its action upon peptide synthetase

Zusammenfassung Zusammenhänge zwischen Struktur und Wirkung bei Chloramphenicol führen zu der Hypothese, dass das Antibiotikum die Peptidsynthetase der Ribosome dadurch hemmt, dass es den Peptidylpartner der Reaktion antagonisiert. Im Einklang damit steht, dass Chloramphenicol sich spezifisch an Ribosome bindet und selektiv die Elongationsphase der Proteinsynthese hemmt.     

Ergot alkaloids modified in the cyclitol moiety

Summary Birch reduction of 9, 10-dihydroergot alkaloids (I) yields a compound to which structureII is assigned.     

The biosynthesis of the thioglucoside moiety of benzyl glucosinolate

Zusammenfassung Phenylacetothiohydroxamat und Thioglukose wurden als mögliche biosynthetische Quellen des thioglukosidischen Schwefelatoms in Benzylglukosinolat (Glucotropaeolin), dem Senfölglukosid der Kapuzinerkresse (Tropaeolum majus L.) untersucht. Die experimentellen Ergebnisse deuten darauf hin, dass Thioglukose eine direkte Vorstufe ist, die mit einer von Phenylalanin abgeleiteten Stickstoffverbindung reagiert.     

The synthesis of a peptide having the structure attributed to a sound habituating material.

A peptide isolated from rats habituated to a sound stimulus has been given the structure (see article) Glu-Ala-Gly-Tyr-Ser-Lys-OH. A synthesis of this compound afforded a product that different from the natural material on the basis of chromatographic and physiological comparisons. The proposed sequence must therefore be in error.     

Paracelsin, a peptide antibiotic containing alpha-aminoisobutyric acid, isolated from Trichoderma reesei Simmons. Part A

A peptide antibiotic has been isolated from Trichoderma reesei QM 9414. Although crystalline and uniform in TLC, this antibiotic could be resolved by HPLC into 3 sequence analogues. The close relationship to alamethicin was proved by chemical and spectroscopic methods, and the formation of ion-conducting pores in lipid bilayers.     

Unexpected collagen crosslinking observed during in vitro radiolabeling of the galactosyl moiety

Aldehyde groups, generated by oxidation of free primary alcohol groups of galactosyl residues of glycoproteins by galactose oxidase, can react with free amino groups on the polypeptide chain through Schiff base formation. Subsequent reduction with tritiated borohydride results in the formation of stable crosslinks instead of the expected generation of radiolabeled alcohol groups. Attempts to perform in vitro radiolabeling of collagen type I by this procedure resulted in undesirable crosslinking with profound alteration of the physical properties that rendered the resulting radiolabeled preparation unsuitable for biochemical studies.     

New insights into copper monooxygenases and peptide amidation: structure, mechanism and function

Many bioactive peptides must be amidated at their carboxy terminus to exhibit full activity. Surprisingly, the amides are not generated by a transamidation reaction. Instead, the hormones are synthesized from glycine-extended intermediates that are transformed into active amidated hormones by oxidative cleavage of the glycine N-C alpha bond. In higher organisms, this reaction is catalyzed by a single bifunctional enzyme, peptidylglycine alpha-amidating monooxygenase (PAM). The PAM gene encodes one polypeptide with two enzymes that catalyze the two sequential reactions required for amidation. Peptidylglycine alpha-hydroxylating monooxygenase (PHM; EC 1.14.17.3) catalyzes the stereospecific hydroxylation of the glycine alpha-carbon of all the peptidylglycine substrates. The second enzyme, peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL; EC 4.3.2.5), generates alpha-amidated peptide product and glyoxylate. PHM contains two redox-active copper atoms that, after reduction by ascorbate, catalyze the reduction of molecular oxygen for the hydroxylation of glycine-extended substrates. The structure of the catalytic core of rat PHM at atomic resolution provides a framework for understanding the broad substrate specificity of PHM, identifying residues critical for PHM activity, and proposing mechanisms for the chemical and electron-transfer steps in catalysis. Since PHM is homologous in sequence and mechanism to dopamine beta-monooxygenase (DBM; EC 1.14.17.1), the enzyme that converts dopamine to norepinephrine during catecholamine biosynthesis, these structural and mechanistic insights are extended to DBM.     

Chemical constituents of the antibiotic fraction ofArnebia nobilis

Zusammenfassung Aus den Wurzeln vonArnebia nobilis wurden 4 antibiotisch wirksame Stoffe isoliert. Die Struktur von dreien wurde aufgeklärt.

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On deputation from the Chemistry Department, Lucknow University.

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To whom enquiries should be made. The isolation of shikonin monoacetate and,-dimethylacrylate fromLithosperm erythrorhizon, I.Morimoto, T.Kishi, S.Ikegana and Y.Hirata, Tetrahedron Lett.4737 (1965), has been brought to our notice since communicating this paper.

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Communication No. 1305 from the Central Drug Research Institute.     

Total synthesis of the antibiotic polymyxin B1

Zusammenfassung Es wird über die Synthese des cyclo-Decapeptides 7, in welchem alle Dab-Reste diel-Konfiguration aufweisen, berichtet. Dieses erwies sich als identisch mit natürlichem Polymyxin B₁ (Figur 2).