Regulation of rat mast cell protease 1 activity : Protease inhibition is prevented by heparin proteoglycan

Sammanfattning

Rat mast cell protease 1 (RMCP-1) is a chymotrypsin-like serine protease (chymase) that is specifically expressed by connective-tissue-type mast cells. It is stored in the secretory granules of the cells in following mast cell activation. The present study was undertaken to examine if the association with heparin proteoglycan influenced the regulation nf RMCP-1 by, various macromolecular protease inhibitors. Endogenous mast cell heparin proteoglycan was shown to significantly block the inhibition of RMCP-1 by the serpins alpha(1)-protease inhibitor and alpha(1)-antichymotrypsin as well as the inhibition by alpha(2)-macroglobulin, soybean trypsin inhibitor and plasma. The blocking of protease inhibition showed an optimum at a RMCP-1/proteoglycan ratio of 5:1 (by mass), corresponding to approximate to 80 RMCP-1 molecules bound/proteoglycan molecule. Chymase activity present on intact peritoneal mast cells, i.e. present in its native complex with heparin proteoglycan, was also shown to be largely resistant to inhibition by alpha(1)-antichymotrypsin and alpha(1)-protease inhibitor. Heparin 10-saccharides and 20-saccharides were inefficient in preventing the interaction of RMCP-1 with alpha(1)-antichymotrypsin, whereas pig mucosal heparin (approximate to 50 monosaccharide units) blocked protease inhibition. We have previously shown that heparin potentiates the catalytic activity of RMCP-1 and, in the present study, we show that the mechanism for chymase activation involves a sixfold reduction of the K-m, (app) value of RMCP-1 for the chromogenic substrate S-2586. Thus, the association of mast cell chymase with heparin proteoglycan may serve both to potentiate the catalytic activity of the enzyme and to increase the life-span of the chymases by preventing their inhibition after exocytosis.

Nyckelord

HEPARIN PROTEOGLYCAN; RAT MAST CELL PROTEASE 1; CHYMASE; MAST CELLS; SERPINS

Publicerad i

European Journal of Biochemistry
1995, Volym: 233, nummer: 1, sidor: 192-199 Utgivare: SPRINGER VERLAG

SLU författare

• Pejler, Gunnar

  • Institutionen för veterinärmedicinsk kemi, Sveriges lantbruksuniversitet
    

• Berg, Lotta

  • Institutionen för veterinärmedicinsk kemi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Cell- och molekylärbiologi


Publikationens identifierare

DOI: https://doi.org/10.1111/j.1432-1033.1995.192_1.x

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/52796