The effects of the Ca2+-activated cysteine proteinase, the rat trypsin-like serine proteinase and bovine trypsin on myofibrillar proteins from rabbit skeletal muscle are compared. 2. Myofibrils that had been treated at neutral pH with the Ca2+-dependent proteinase and with the rat enzyme were (a) analyzed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and (b) examined in the elec...

Four Ca2+-dependent proteinase activities in lobster claw and abdominal muscle have been resolved by high-performance liquid chromatography on gel filtration and ion-exchange columns. These activities, which do not appear to be generated by autolytic or other degradative processes, differed from each other in molecular weight (peak I, Mr = 310,000; peak IIa, Mr = 125,000; peak IIb, Mr = 195,000...

Two proteinases (proteinases I and II) have been purified from Crotalus adamanteus venom to the stage of electrophoretic homogeneity and proteinase II has been crystallized. The proteinases differ slightly in molecular weight and amino acid composition. Both are metalloenzymes requiring Zn2+ or Ca2+, or both; neither requires thiol compounds for activation. The proteinases are free of esterolyt...

Human pulmonary alveolar macrophages obtained by bronchoalveolar lavage from both normal controls and smokers secreted in vitro a neutral proteinase that degraded denatured collagens. Optimal expression of the proteinase was detected after 3-5 d of culture. The proteinase could not be detected in the media of cultures that had been treated with 0.5 gg/ml of cycloheximide. The gelatinase had an ...

Although it is known that most of the plasma proteinase inhibitors form complexes with proteinases that are not dissociated by SDS (sodium dodecyl sulphate), there has been disagreement as to whether this is true for a2M ( a2-macroglobulin). We have examined the stability to SDS with reduction of complexes between a2M and several 125I-labelled proteinases (trypsin, plasmin, leucocyte elastase, ...

The ability of numerous microorganisms to cause disease relies upon the highly regulated expression of secreted proteinases. In this study, mutagenesis with a novel derivative of Tn4001 was used to identify genes required for the expression of the secreted cysteine proteinase (SCP) of the pathogenic Gram-positive bacterium Streptococcus pyogenes. Designated as Rop loci (regulation of proteinase...

Proteolytic activity of the bovine rumen microflora was studied with azocasein as the substrate. Approximately 25% of the proteolytic activity of rumen contents was recovered in the strained rumen fluid fraction, and the balance of the activity was associated with the particulate fraction. The proportion of proteinase activity associated with particulate material decreased when the quantity of ...

Autocatalytic degradation of purified Bacillus subtilis neutral proteinase was examined under various conditions. At elevated temperatures, under non-inhibitory conditions, mature protein was rapidly degraded, but no accumulation of specific breakdown products occurred. However, by incubating purified neutral proteinase on ice during extended periods of time, specific peptides accumulated. Thes...

Grown in dialysate broth at a pH between 5.5 and 6.5, some strains of group A streptococci elaborate the precursor of a proteolytic enzyme. Within this range of hydrogen concentration the precursor is also produced when the streptococci are suspended in a peptone dialysate containing glucose and incubated at 37 degrees C. The precursor does not appear to be produced at a neutral or alkaline rea...

A profound decrease in activities of the two lysosomal serine proteinases, elastase, and cathepsin G, was found in neutrophils of four independent beige mutants. Elastase and cathepsin G activities were assayed with the specific synthetic substrates MeO-Suc-Ala-Ala-Pro-Val-MCA and Suc-Ala-Ala-Pro-Phe-pNA, respectively. The defect is intrinsic to cells of beige mice, since transplantation of bon...