CRCU

Chemical Research in Chinese Universities ›› 2006, Vol. 22 ›› Issue (1): 65-67.

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Peptidase Activities of Tripeptidyl Peptidase Ⅰ(TPP Ⅰ): Exopeptidase and Endopeptidase

DU Pei-ge1, AN Li-ping1, QIU Fang-ping2, LU Gang1   

  1. 1. Clinical Diagnosis Laboratory of Beihua University, Jilin 132013, P. R. China;
    2. College of Biological Engineering, Changchun University of Technology, Changchun 130012, P. R. China
  • Received:2005-03-02 Online:2006-02-24 Published:2011-08-06
  • Supported by:

    Supported by the Scientific Research Fund for the Returned Overseas Chinese Scholars, State Education Ministry.

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Abstract: The defect of TPP Ⅰ causes a disease, late infantile neuronal ceroid lipofuscinosis(LINCL, CLN2). To investigate the bio-activity of tripeptidyl peptidase Ⅰ(TPP Ⅰ) from rat kidneys, the effects of digestion of angiotensin Ⅱ(Ang Ⅱ) and a synthetic endo-type substrate(Gly1-Lys-Pro-Iie-Pro5-Phe-Phe-Arg-Leu-Lys10) via TPP Ⅰ were analyzed by HPLC and TOF-MS. The data suggest that the degradation rate of Ang Ⅱ can reach 18.2% by the rat TPP Ⅰ and DRV(Asp-Arg-Val) can be released from N-termini of Ang Ⅱ within 16 h. In addition, the synthetic endo-type substrate is cleaved at the same position between Phe6 and Phe7. Accordingly, TPP Ⅰ shows two kinds of peptidase activities. One is a tripeptidyl peptidase activity and the other is a pepstatin insensitive carboxyl endopeptidase activity. Tripeptidyl peptidase activity and pepstatin insensitive carboxyl endopeptidase activity seem to be dual phases of one enzyme, TPP Ⅰ.

Key words: Rat TPP Ⅰ, Angiotensin Ⅱ, Endo-type substrate, Endopeptidase activity