Enzyme antigens associated with pigeon breeder's disease. I. Isolation and characterization of basic hydrolases

A survey of the hydrolytic enzymes present in pigeon dropping extracts (PDE) has shown that this material contains a variety of proteolytic and nonproteolytic activities. These enzymes were separated into their basic and acidic components by chromatography on DEAE-cellulose. Staining of immunoprecipitates with specific chromogenic substrates demonstrated the presence of antibodies in symptomatic breeders to several of the basic enzymes in PDE. Five distinct hydrolytic activities were isolated from the basic group of enzymes. Trypsin, elastase, and two forms of collagenase were the specific proteolytic activities isolated. A phospholipase was also purified from these preparations. The purified elastase consisted of a single polypeptide chain (M_r=22,000). The purified trypsin had a molecular weight (M_r=25,000) and charge similar to those reported for elastase and, like elastase, the trypsin from PDE appeared to be composed of a single polypeptide chain. Two molecular weight forms of collagenase were found; both hydrolyzed bovine collagen. The high-molecular-weight collagenase (M_r=51,000) was shown to be a glycoprotein consisting of two polypeptides (M_r=24,000). It was readily separated from the low-molecular-weight collagenase (M_r=15,000) by gel filtration. The phospholipase (M_r=99,000) appeared to be a dimer. The relevance of these enzymes to the development of pigeon breeder's disease is discussed.