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Biomedical subjects

C A Benassi

Publications and source records attributed to C A Benassi.

At least 37 records · Page 2Linked to original sources
PubMed1977

Drug-protein interaction: the binding of cephalosporins to albumins.

The binding of some cephalosporin antibiotics, namely cephalothin, cephaloridine and cephalexin, to serum albumins was quantitized using a fluorescence probe technique. The results suggest that these drugs bind to hydrophobic sites on serum albumins. The association constants of the three drugs with bovine serum albumin showed the strongest binding for cephalothin (Ka 1.2 x 10(3) M(1)) and weaker ones for cephaloridine and cephalexin (Ka 0.59 and 0.4 x 10(3) M(-1)). Serum albumin from different species was also investigated, only minor variations in the binding properties being found.

Animals↗
PubMed1976

On the reaction of acetamidomethanol with native and reduced bovine pancreatic trypsin inhibtor (Kunitz inhibitor).

The stability of native and reduced bovine pancreatic trypsin inhibitor (Kunitz inhibitor) in anhydrous hydrogen fluoride and their reaction with acetamidomethanol, in the same solvent, have been investigated. The bovine Kunitz inhibitor appears to be stable in liquid hydrogen fluoride but the reduced molecule loses about 50% of its ability to regain inhibitory power, upon air oxidation, by exposure to this solvent. Tyrosine residues appear to be affected by acetamidomethylation of the native protein to give a modified inhibitor which is still highly active in inhibiting trypsin. The extent of correct refolding, upon reoxidation, of the reduced tyrosine modified-inhibitor is greatly diminished. Tyrosine modification can be prevented by carrying out the acetamidomethylation reaction in the presence of excess anisole. The stability constants and the standard free energies of binding of the complexes between trypsin and the native and the tyrosine modified-inhibitor have been determined.

Acetamides↗
PubMed1976

Studies on trypsin inhibitors. Part I. Synthesis of protected peptides related to sequence 1-10 of porcine pancreatic secretory trypsin inhibitor II (Kazal).

The general strategy for the synthesis, by conventional procedures, of the entire sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal) is discussed. The synthesis of two protected peptides corresponding to positions 2-10 and 1-10 of the proposed primary structure of the inhibitor is described. The heptapeptide free base threonyl-S-acetamidomethylcysteinylthreonylseryl-gamma-tert-butylglutamylvalylserine tert-butyloxycarbonylhydrazide (sequence 4-10) was acylated, by the azide procedure, with either the dipeptide benzyloxycarbonyl-gamma-tert-butylglutamylalanine hydrazide (sequence 2-3) or the tripeptide Nalpha-benzyloxycarbonyl-Nomega-nitroarginylglutamylala-nine hydrazide (sequence 1-3). The stereochemical homogeneity of the resulting peptides, benzyloxycarbonyl-gamma-tert-butylglutamylalanylthreonyl-S-acetamidomethyl-cysteinylthreonylseryl-gamma-tert-butylglutamylvalylserine tert-butyloxycarbonylhydrazide and Nalpha-benzyloxycarbonyl-Nomega-nitroarginylglutamylalanylthreonyl-S-acetamido-methylcysteinylthreonylseryl-gamma-tert-butylglutamylvalylserine tert-butyloxycarbonyl-hydrazide, was assessed, after partial deprotection with liquid hydrogen fluoride, by digestion with aminopeptidase M followed by quantitative amino acid analysis.

Alanine↗
PubMed1976

Studies on trypsin inhibitors. Part IV, Synthesis of the protected undecapeptide (sequence 25-35) of porcine pancreatic secretory trypsin inhibitor II (Kazal).

Synthesis is described of the protected undecapeptide tert-butyloxycarbonylisoleucyl-threonyltyrosylserylasparaginyl-gamma-tert-butylglutamyl-S-acetamidomethylcysteinyl-valylleucyl-S-acetamidomethylcysteinylseriny hydrazide corresponding to positions 25-35 of the amino acid sequence of porcine pancreatic secretory trypsin inhibitor II (Kazal). The hepatapeptide free base methyl asparaginyl-gamma-tert-butylglutamyl-S-acetamidomethylcysteinylvalylleucyl-S-acetamidomethylcysteinylserinate (sequency 29-35) was acylated, by the azide procedure, with the tetrapeptide tert-butyloxycarbonl-isoleucylthreonyltyrosylserine hydrazide /sequence 25-28) and the resulting tert-butyloxycarbonylundecapeptide methyl ester was transformed into the corresponding hydrazide by hydrazinolysis. The stereochemical homogeneity of the final product was assessed, after partial deprotection with aqueous 90% trifuoroacetic acid, by digestion with papain and aminopeptidase M followed by quantitative amino acid analysis.

Amino Acid Sequence↗
PubMed1976

[Use of oximinoiminopyrrazoline esters in the synthesis of solids phase peptides: synthesis of bradykinin].

Since oximinyliminopyrrazoline ester (OPmp) present a peculiar characteristic in the omogenous peptide synthesis, the use of them, also in the synthesis of bradikinine by the solid phase technique, was duly taken into consideration and tried out. This synthesis was achieved by employing N-protected amino acid OPmp esters containing a methoxycarbonyl or a benzylaminocarbonyl as the acyl function in position 5 of the pyrazoline ring. No significant differences were found in the reactivity of such derivatives in respect of OPmp esters containing the benzyloxycarbonylglycyl moiety. The biological activity of the synthetized braikinine is similar to that of a sample of natural "standard".

Bradykinin↗
PubMed1975

[Esters and amides of salicyloylamino acids].

N-Salicyloylamino acids, esters and amides have been prepared by the usual condensation methods and also by methods which may demonstrate 2-(o-hydroxyphenyl)oxazoline-5-ones as possible reaction intermediates. Some derivatives display pharmacological activities.

Amino Acids↗