PMID: 4506775Sep 1, 1972Paper

Self purification of two serine endopeptidases

Proceedings of the National Academy of Sciences of the United States of America
W M AwadT P Toomey


We have reported that a serine protease from Pronase, homologous with bovine chymotrypsin, is both active and stable in 6 M guanidinium chloride. The present investigation examined the possibility that this unique property might be used to permit the enzyme to engage in its own purification by cleaving companion proteins to low-molecular-weight products. Analysis with model substrates of the several specific activities that were originally present revealed that only the activity against Nalpha-acetyl-L-tyrosine ethyl ester was demonstrable after incubation for 100 hr in the denaturant. After a moderate loss within the first 24 hr, the remaining activity against this ester was conserved for many days thereafter. Pronase was routinely incubated for 1 week at 22 degrees in 6 M guanidinium chloride at pH 8.0 where the esterases showed maximal activity. Analysis of the products of incubation revealed unexpectedly the presence of two serine proteases that were easily separated. After purification to homogeneity these components proved themselves to be the previously demonstrated subtilisin-like and stable chymotrypsin-like enzymes. The only amino-terminal residue of the chymotrypsin-like enzyme is isoleucine, as it is in the earlier,...Continue Reading


Feb 21, 1967·Biochimica Et Biophysica Acta·K R Woods, K T Wang
Dec 28, 1971·Biochimica Et Biophysica Acta·C E Stauffer, J F Sullivan
Jun 11, 1963·Biochimica Et Biophysica Acta·W M Awad, P E WILCOX
Mar 28, 1964·Nature·B S HARTLEY


Jul 1, 1982·Archives of Biochemistry and Biophysics·P CupoW M Awad
Jul 1, 1985·Archives of Biochemistry and Biophysics·A T FojoW M Awad
Jul 24, 1974·Biochemical and Biophysical Research Communications·W M Awad, M S Ochoa
Jan 1, 1976·Journal of Cellular Physiology·R E SchmitterJ W Hastings
Aug 1, 1987·International Journal of Peptide and Protein Research·E R JohnsonB R Lindley

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