Parasites, Hosts and Diseases

The Korea Society for Parasitology and Tropical Medicine (대한기생충학·열대의학회)
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Purification of a 68-kDa cysteine proteinase from crude extract of Pneumocystis carinii

  • Choi, Min-Ho (Department of Parasitology Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research) ;
  • Chung, Byung-Suk (Department of Parasitology Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research) ;
  • Chung, Young-Bae (Department of Parasitology Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research) ;
  • Yu, Jae-Ran (Department of Parasitology, College of medicine, Konkuk University) ;
  • Cho, Sang-Rock (Department of Cardiovascular Surgery, Kangnam General Hospital Public Corporation) ;
  • Hong, Sung-Tae (Department of Parasitology Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center)
  • Published : 2000.09.01
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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 Iysis 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 rnacrornolecules 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.

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