A rapid procedure for the large scale purification of elastase and cathepsin G from human sputum.

A procedure is described which permits the rapid isolation of large amounts 
of elastase and cathepsin G from purulent sputum. This procedure involves: 
(1) digestion of sputum with DNase, (2) extraction of the insoluble 
residue that remains with 1 M NaCl, pH 8, (3) affinity 
chromatography on Sepharose-bound Trasylol, and (4) separation of the two enzymes 
by chromatogrphy on CM-Sephadex. Starting with 500 g of sputum it 
was possible to isolate 175 mg of each of these two 
enzymes within 7 to 10 days. Active site titration indicated both 
enzymes to be at least 97% pure. Disc gel electrophoresis in 
the presence and absence of SDS and amino acid sequence of 
the N-terminal region support the conclusion that the elastase and cathepsin 
G isolated from sputum are identical to the same enzymes isolated 
directly from the leukocytes of human blood. 