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R Coccia

Publications and source records attributed to R Coccia.

47 records · Page 3Linked to original sources
PubMedDate not supplied

Oxidative deamination of S-aminopropylcysteine and S-aminoethylhomocysteine.

S-aminopropylcysteine and S-aminoethylhomocysteine are oxidized by snake venom L-amino acid oxidase in the presence of catalase with formation of the respective ketoderivatives. Only the ketoderivative of S-aminopropylcysteine cyclizes to give a seven membered ring (ketimine) absorbing at 296 nm. In the absence of catalase both ketoderivatives are oxidatively decarboxylated.

Amines↗
PubMedDate not supplied

Pyridoxal phosphate catalyzed alpha-beta elimination of selenahomolysine.

In the presence of pyridoxal phosphate selenahomolysine undergoes alpha-beta elimination with production of pyruvate, ammonia and selenohomocysteamine. If the reaction occurs in anaerobic conditions the coupling of pyridoxal phosphate with selenohomocysteamine in a tetrahydro-selenazine ring may be detected by the appearance of an absorption band at 320 nm. In the presence of air the autoxidation rate of selenohomocysteamine is too high to allow the detection of the selenazine derivative. The results obtained add to the previously reported ones indicating that selenium- and sulfur-containing aminoacids react in quite the same way in the non enzymic model studied.

Catalysis↗
PubMedDate not supplied

Thialysine and selenalysine incorporation into CHO cell proteins and its effects on cell growth.

CHO cells can incorporate into proteins both thialysine and selenalysine when both are present together in the culture medium. Thialysine and selenalysine inhibit cell growth and cell viability. The inhibitory effect of either analog is additive. The inhibition of cell viability is related to the extent of protein lysine substitution by thialysine or selenalysine; it is however irrelevant whether lysine is substituted by one or the other analog or by both.

Animals↗
PubMedDate not supplied

Oxidative deamination of S-(1-carboxyethyl)-L-cysteine and S-(1-carboxypropyl)-L-cysteine by L-aminoacid oxidase.

S-(1-carboxyethyl)-L-cysteine (1-CEC) and S-(1-carboxypropyl)-L-cysteine (1-CPC) are oxidatively deaminated by L-aminoacid oxidase with consumption of half a mole of oxygen per mole of substrate in the presence of catalase. This reaction gives rise to the corresponding alpha-ketoacids, identified by some chemical and chromatographic tests and by comparison with synthetic compounds. It has been possible, therefore, to demonstrate that S-(1-carboxyethyl)-thiopvruvic acid (1-CETP) and S-(1-carboxypropyl)-thiopvruvic acid (1-CPTP) are the main products of oxidative deamination of 1-CEC and 1-CPC.

Amino Acid Oxidoreductases↗
PubMedDate not supplied

Synthesis and chromatographic properties of S-(1-carboxyethyl)-L-cysteine and S-(1-carboxypropyl)-L-cysteine.

Details are reported for the synthesis of S-(1-carboxyethyl)-L-cysteine (1-CEC) and S-(1-carboxypropyl)-L-cysteine (1-CPC) from cysteine and 2-bromopropionic acid or 2-bromobutyric acid, respectively. Some analytical data and the behaviour of these two compounds on paper and ion-exchange chromatography are also reported, which allow their identification.

Amino Acid Oxidoreductases↗
PubMedDate not supplied

Oxidation of D-thiazolidine-4-carboxylic acid by hog kidney D-aminoacid oxidase.

D-Thiazolidine-4-carboxylic acid is a good substrate for hog kidney D-aminoacid oxidase. Data are presented showing that the only oxidation product is delta 3-thiazoline-4-carboxylic acid, which does not undergo further spontaneous degradation. Thus, the oxidation of D-thiazolidine-4-carboxylic acid by D-aminoacid oxidase differs considerably from the oxidation of its L-isomer catalyzed by rat liver mitochondria which gives as final product N-formylcystine, possibly through the intermediate delta 2-thiazoline-4-carboxylic acid.

Animals↗
PubMedDate not supplied

Thialysine and selenalysine utilization for protein synthesis by E. coli in comparison with lysine.

Utilization of thialysine and selenalysine for protein synthesis by a lysine requiring E. coli mutant was studied. Incorporation into proteins of thialysine or selenalysine, added to culture medium together with lysine, becomes evident when the amount of available lysine in the medium is highly reduced, that is the mutant utilizes the isologs only after all the available natural aminoacid has been utilized. Compared to selenalysine, thialysine is better utilized; when both isologs are present in the medium at equal concentrations, up to 46% of protein lysine is substituted by thialysine and only 12% by selenalysine.

Cysteine↗