Proteolytic and partial characterization of human sperm-surface glycopeptides

Sperm-surface glycopeptides were obtained from intact sperm membranes after proteolytic release by different enzymatic treatments such as autoproteolysis, trypsin, papain and pronase. Glycopeptides were isolated, their properties and composition were examined, and their monosaccharide and amino acid constituents were characterized. The monosaccharides identified were fucose, mannose, galactose, N-acetylglucosamine, and N-acetylgalactosamine, which form part of more than one type of oligosaccharide units. Autoproteolytic treatmentmainly provided O-glycosidic type oligosaccharides, while a mixture of O- and N-glycosidic oligosaccharides was obtained in variable proportions when treated with trypsin, papain or pronase. The highest degree of peptide cleavage was obtained with pronase. Despite the higher yields reached with trypsin, these glycopeptides contain the lowest percentage of oligosaccharide chains. Proteolytic treatment provides a simple, rapid procedure for the isolation of glycopeptides from the sperm surface.

Solubilidade e grau de hidrolise da carne bovina tratada por enzimas / Solubility and hydrolysis degree of meat treated by enzymes

Sao realizados estudos relacionados a acao enzimatica da papaina, tripsina e protease microbiana, isoladas e em mistura, na solubilizacao das proteinas da carne bovina. A eficiencia do ataque das enzimas sobre as proteinas da carne bovina foi: mistura de enzimas > papaina > tripsina > protease microbiana. Passados 120 minutos de hidrolise nas condicoes de trabalho os valores de graus Brix, solidos soluveis e grau de hidrolise mantiveram-se inalterados. O grau de hidrolise atingido foi de 48,1% para a papaina, 48,6% para a tripsina, 37,1% para a protease microbiana e 41,0% com a mistura de enzimas

Papain-catalyzed esterification of N-tert-butyloxycarbonyl and N-benzyloxycarbonyl amino acids

1. simple method is described for the preparation of optically active N-tert-butyloxycarbonyl (Boc) and N-benzyloxycarbonyl (Z) amino acid methyl and ethyl esters by papin-catalyzed esterification. 2. N-protected amino acid (50mM) were incubated with 25 micronM papain in 1 mM sodium acetate buffer, pH 4.7, containing 50% (v/v) methanol or ethanol for 24 h at 3-C. 3. Methyl and ethyl esters of 20 Boc-and Z-amino acids were prepared in yields from 28 to 98%. Among these, the following compounds have not previously been described (yield): Boc-Cys-(Mob)-OMe (98%); Boc-Lys-(Dmc)-OMe (78%); Boc-Ser-(Bzl)-OMe (53%); Boc-Arg-(Tos)-OMe (43%); Boc-Cys-(Mob)-OEt (52%); Boc-Trp-OEt (63%); Boc-Glu-(OBzl)-OEt (39%); Boc-Phe-OEt (43%); Z-Lys-(Z)-OEt (62%); /z-Trp-OEt (46%). 4. This method is effective for the enzymatic synthesis of N-protected amino acid esters and is sespecially useful for the preparation of Boc-amino acid esters because of the extreme lability of the Boc protecting group in acid medium