Salivary histatin 5 is a potent competitive inhibitor of the cysteine proteinase clostripain

FEBS Letters

Kagan, Herbert M.²  Oppenheim, Frank G.¹  Grogan, James¹  Gusman, Heloisa¹  Troxler, Robert F.¹ 

[1] Department of Periodontology and Oral Biology, Boston University Goldman School of Dental Medicine, 700 Albany St. W201, Boston, MA 02118-2392, USA;Department of Biochemistry, Boston University School of Medicine, 80 E. Concord St., Boston, MA 02118-2392, USA

关键词: Histatin 5;    Saliva;    Clostripain;    Cysteine proteinase inhibition;    Leupeptin;    Clostridium histolyticum;   

DOI  :  10.1016/S0014-5793(01)02077-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Histatin 5 is a low molecular weight salivary protein which is known to exhibit inhibitory activity against several proteinases, including the cysteine proteinases gingipains. The purpose of this study was to characterize the effect of salivary histatin on the proteolytic activity of the cysteine proteinase clostripain derived from the pathogen Clostridium histolyticum. Using a synthetic nitroanilide substrate, we studied in detail the inhibition of clostripain by histatin 5 and compared the effect of this peptide to that of leupeptin, a known competitive inhibitor of clostripain. It was found that the concentration of histatin 5 required to inhibit 50% of clostripain activity was 23.6±1.6 nM. Kinetic analysis revealed that histatin 5 is a competitive inhibitor of clostripain with an inhibition constant (K _i) of 10 nM. The K _i for the inhibition of clostripain activity against nitroanilide substrate by leupeptin was found to be 60 nM, significantly higher than that of histatin 5. Thus, histatin 5 inhibits clostripain more effectively than leupeptin and other cysteine protease inhibitors studied here. No significant proteolysis of histatin 5 was observed when histatin 5 was incubated at physiologic concentrations with clostripain. The potent inhibition of clostripain by histatin 5 points towards the possibility that this protein may prevent establishment of clostridial infections and therefore may have significant potential for the treatment of diseases associated with this enzyme.

【 授权许可】

Unknown