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Title: Matrix metalloprotease 2-mediated activation of Ca2+-ATPase by superoxide radical (O2.-) in plasma membrane of bovine pulmonary vascular smooth muscle
Authors: Mandai, Malay
Das, Sudip
Chakraborti, Tapati
Chakraborti, Sajal
Issue Date: Dec-2002
Publisher: NISCAIR-CSIR, India
Abstract: The role of the matrix metalloprotease-2 (MMP-2) in regulating Ca2+-ATPase activity in bovine pulmonary artery smooth muscle plasma membranes during treatment with the O2.-generating system, hypoxanthine (HPX) plus xanthine oxidase (XO) has been studied. The smooth muscle membranes possess matrix metalloprotease (MMP) activity in gelatin Zymogram, having an apparent molecular mass of 72 kDa; the activity is inhibited by the tissue inhibitor of metalloprotease-2 (TIMP-2). Since both protease and MMP-2 have same molecular mass and are inhibited by TIMP-2, it may, therefore, be suggested that the protease is the MMP-2. Treatment of the smooth muscle membrane suspension with the O2.- generating system stimulates MMP-2 activity, as evidenced by an apparent increase in the intensity of the protease activity. O2.- also enhances [14C]-gelatin degradation and Ca2+-ATPase activity. The increase in MMP activity, assessed by [14C] -gelatin degradation and Ca2+- ATPase activity are inhibited upon pretreatment with superoxide dismutase (SOD). The O2.- triggered MMP and Ca2+-ATPase activities in the membrane are found to be inhibited by TIMP-2 . The stimulation of the MMP and Ca2+-ATPase activities remain unaffected by the inhibitors of serine, thiol and cysteine groups of proteases such as phenylmethylsulfonylfluo ride (PMSF). Bowman Birk inhibitor (BBI), chymostatin, N-ethylmaleimide, leupeptin. antipain and pepstatin. Adding pure bovine MMP-2 to the smooth muscle membrane suspension causes an increase in Ca2+-ATPase activity, but the pretreatment with TIMP-2 inhibits the increase in the enzyme activity.
Page(s): 390-396
ISSN: 0975-0959 (Online); 0301-1208 (Print)
Appears in Collections: IJBB Vol.39(6) [December 2002]

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