The activities of three commercial products of papain were compared as supplied and after activation, and when used in the enzyme-serum method for rhesus (D) grouping. Certain dangers in activation became apparent, and accurate determination of the proportions of papain to anti-D appeared more important than indiscriminate activation without reference to the initial enzyme activity. A technique...

A novel fragment-based drug discovery approach is reported which irreversibly tethers drug-like fragments to catalytic cysteines. We attached an electrophile to 100 fragments without significant alterations in the reactivity of the electrophile. A mass spectrometry assay discovered three nonpeptidic inhibitors of the cysteine protease papain. The identified compounds display the characteristics...

A globulin fraction, isolated from black beans (Phaseolus vulgaris), was resistant to hydrolysis by pepsin, trypsin, chymotrypsin, papain, ficin, hurain, and subtilisin. After denaturation of the globulin by heat or urea, only slight hydrolysis by enzymes could be detected. The activity of all seven proteinases on their respective substrates was inhibited by the bean globulin. Preincubation of ...

Among the different experimental agents that act upon the endochondral growth of laboratory animals. crude papain seems to be one of the most powerful (Hulth 1958). Papain acts rapidly on the cartilage and, when injected repeatedly, causes premature ossification of the epiphysial lines. Other factors that retard the longitudinal growth are endocrine disorders, such as those caused by hypophysec...

The amino acid sequences of rat liver lysosomal thiol endopeptidases, cathepsins B and H, are presented and compared with that of the plant thiol protease papain. The 252-residue sequence of cathepsin B and the 220-residue sequence of cathepsin H were determined largely by automated Edman degradation of their intact polypeptide chains and of the two chains of each enzyme generated by limited pr...

A high-molecular-weight cysteine proteinase inhibitor (CPI) was purified from chicken (Gallus gallus) plasma using polyethylene glycol (PEG) fractionation and affinity chromatography on carboxymethyl-papain-Sepharose-4B. The CPI was purified 96.8-fold with a yield of 28.9%. Based on inhibitory activity staining for papain, CPI was shown to have an apparent molecular mass of 122 kDa. No inhibito...

The tryptophan-containing peptides were isolated from the chymotryptic digest of S-carboxymethylated papain. Residue 175, which is strongly hydrogen-bonded to the active-site histidine residue in the tertiary structure of papain, is asparagine, confirming the work of Kimmel, Rogers & Smith (1965). Its function is probably to maintain the orientation and tautomeric state of the imidazole ring of...

Although the milk-clotting action of papain has been recognized for many years, this property of the enzyme has received little quantitative attention. It appears to be, however, a characteristic property of the proteolytic component of this enzyme system. Various workers have brought forth evidence as to the composite nature of the papain system, which has at least two components. In the most ...

The catalytic activity of several proteolytic enzymes is altered by high concentrations of urea and guanidine salts (2-4). These studies, in conjunction with certain physical data, indicate that hydrogen bonding in the secondary structure of these enzymes is essential for maintenance of their catalytic function. Because of the increasing amount of information that is available concerning the st...

Mouse macrophage elastase, a metalloproteinase secreted by inflammatory macrophages, catalyzed the limited proteolysis of selected subclasses of mouse immunoglobulins, including monomeric IgG2a, IgG3, and some forms of IgG2b. Mouse IgG1 was resistant to elastase degradation; however, human IgG1 was degraded. IgG3 in immune complexes was cleaved in a manner similar to that of monomeric IgG3. Deg...