J. M. Cei

ISOLATION AND AMINO ACID SEQUENCE OF PHYSALAEMIN, THE MAIN ACTIVE POLYPEPTIDE OF THE SKIN OF PHYSALAEMUS FUSCUMACULATUS.

Abstract Crude methanol extracts of fresh and dried skins of Physalaemus fuscumaculatus , a South American amphibian, were subjected successively to chromatography on alkaline alumina and to countercurrent distribution. The main active constituent of these extracts, the polypeptide physalaemin , was thus obtained in a pure form. Total and partial acid hydrolysis, fission with trypsin and chymotrypsin, and end-group determination experiments demonstrated that physalaemin is an endecapeptide having the following amino acid composition and sequence: Pyr-Ala-Asp(OH)-Pro-Asp(NH 2 )-Lys-Phe-Tyr-Gly-Leu-Met-NH 2 Some anomalies in the trypsin and chymotrypsin fission of physalaemin are discussed, and the strict chemical resemblance between physalaemin and eledoisin is pointed out.

Occurrence of new imidazolealkylamines (Spinaceamine and 6-Methylspinaceamine) in skin extracts ofLeptodactylus pentadactylus labyrinthicus

Estratti di pelle diLeptodactylus pentadactylus labyrinthicus contengono elevati quantitativi di imidazolalchilamine, fra cui due derivati imidazo-c-piridinici finora ignoti in natura: la spinaceamina e la 6-metilspinaceamina.

5-Methoxy- and 5-Hydroxyindoles in the skin of Bufo alvarius

Abstract The skin of Bufo alvarius, a desert toad of Arizona, contains a number of indolealkylamines and their metabolites belonging to the common series of 5-hydroxyindolealkylamines and to the unusual series of 5-methoxyindolealkyIamines. The most abundant representative of 5-hydroxyindolealkylamines is, as in numerous other toads, bufotenine (up to 3 mg per g dry skin), the most abundant representative of 5-methoxyindolealkylamines, O-methylbufotenine. In parotoid and coxal glands as much as 5–15 per cent of the dry weight is made up by this compound. Natural O-methylbufotenine has been isolated in a pure form and its identity with synthetic O-methylbufotenine definitely established. The B. alvarius skin presents three sulphur-containing indolealkylamines: one is bufoviridine, the well known O-sulphate of bufotenine, the other two are completely new compounds with sulphuric acid probably attached to the > NH group of the indole nucleus. All the hitherto described metabolites arising from the oxidative deamination of 5-hydroxy- and 5-methoxy-indolealkylamines may be found in the B. alvarius skin: 5-hydroxytryptophol, 5-hydroxyindoleacetic acid, 5-methoxytryptophol and 5-methoxyindoleacetic acid. The occurrence of the above compounds points to the necessary presence in B. alvarius skin of a number of enzymes: tryptophan 5-hydroxylase, catalysing the formation of 5-hydroxytryptophan, aromatic L-aminoacid decarboxylase producing the decarboxylation of 5-hydroxytryptophan to 5-hydroxytryptamine, N-methyl transferase and 5-hydroxyindole-O-methyl transferase giving origin to the N-methyl and O-methylindolealkylamines, and finally sulphoconjugases catalysing the linkage of sulphuric acid to the 5-hydroxy group and the > NH group of the indole nucleus. The exceptionally rich sample card of indolealkylamines in the skin of B. alvarius seems of interest not only from the point of view of comparative biochemistry, but also from that of comparative enzymology and biochemical taxonomy.

Indole-, imidazole-, and phenyl-alkylamines in the skin of thirteen Leptodactylus species

Abstract The skin of thirteen Leptodactylus species and sub-species has been examined in regard to its content in biogenic amines. This tissue presents, especially in Leptodactylus pentadactylus labyrinthicus and some other species, an unusually rich miscellany of amines, including at least two indolealkylamines (5-hydroxytryptamine and bufotenidine), three hydroxyphenylalkylamines (p-tyramine, candicine, leptodactyline) and five imidazolealkylamines (histamine, N-methylhistamine, N,N-dimethylhistamine, spinaceamine and 6-methylspinaceamine). It is concluded that the Leptodactylus skin must possess aromatic acid decarboxylase activity, tryptophan-5-hydroxylase activity and N-methyltransferase activity. The skin of nearly every Leptodactylus species and sub-species is characterized by a particular spectrum of amines, which evidently may help in systematies of these species.

5-Methoxy- and 5-hydroxy-indolealkylamines in the skin ofBufo alvarius

Gli estratti di pelle diBufo alvarius, rospo delle regioni desertiche del Nord America, contengono, oltre alle consuete 5-idrossiindolalchilamine (5-HT, N-metil-5-HT, bufotenina) enormi quantitativi di derivati 5-metossiindolici, rappresentati soprattutto daO-metilbufotenina. Questa può giungere a costituire fino il 16% del peso delle ghiandole cutanee secche. Si insiste sulla probabile presenza di 5-idrossiindolo-O-metiltransferasi nella pelle diBufo alvarius.

A Bradykinin-Like Endecapeptide of the Skin of Phyllomedusa Rohdei

In the preceding communication Erspamer and Anastasi reported that a number of peptides active on smooth muscle could be extracted from the skin of the South American amphibian Phyllomedusa rohdei. We will now report briefly on the isolation and determination of the structure of phyllokinin, a peptide which strikingly resembles bradykinin in its pharmacological actions.