title: Purification of a 68-kDa cysteine proteinase from crude extract of Pneumocystis carinii.
abstract: The present study intended to verify activities of cysteine proteinase of Pneumocystis carinii from rats and to purify the enzyme. In order to exclude the contamination of host-derived enzymes, concentrates of P. carinii was primarily treated with a mixture of proteinase inhibitors before lysis of P. carinii. A 68-kDa cysteine proteinase was finally purified from the crude extract of P. carinii by 4 sequential chromatographic methods. The enzyme showed an optimal activity at pH 5.5 in 0.1 M sodium acetate, and its activity was specifically inhibited by L-trans-epoxy-succinylleucylamido (4-guanidino) butane (E-64) and iodoacetic acid, suggesting that the enzyme is a cysteine proteinase. The 68-kDa proteinase weakly digested macromolecules such as collagen, hemoglobin and fibronectin. The present study demonstrated the activity of cysteine proteinase at the 68-kDa band of P. carinii, and purified and characterized the molecule.
authors.affiliation: Department of Parasitology, Seoul National University College of Medicine, Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Choi
authors.forename: B S
authors.initials: BS
authors.lastname: Chung
authors.forename: Y B
authors.initials: YB
authors.lastname: Chung
authors.forename: J R
authors.initials: JR
authors.lastname: Yu
authors.forename: S R
authors.initials: SR
authors.lastname: Cho
authors.forename: S T
authors.initials: ST
authors.lastname: Hong
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000302:isolation & purification* / Q000494:pharmacology; D005353:Fibronectins / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D046911:Macromolecular Substances; D008970:Molecular Weight; D011010:Pneumocystis / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005353:Fibronectins; D006454:Hemoglobins; D046911:Macromolecular Substances; D003094:Collagen; D003546:Cysteine Endopeptidases