Open AccessProstromelysin‐1 (proMMP‐3) stimulates plasminogen activation by tissue‐type plasminogen activator
Author(s) -
Arza Begoña,
Hoylaerts Marc F.,
Félez Jordi,
Collen Désiré,
Lijnen H. Roger
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01732.x
Subject(s) - plasminogen activator , tissue plasminogen activator , chemistry , medicine , biochemistry
Matrix metalloproteinase‐3 (MMP‐3 or stromelysin‐1) specifically binds to tissue‐type plasminogen activator (t‐PA), without however, hydrolyzing the protein. Binding affinity to proMMP‐3 is similar to single chain t‐PA, two chain t‐PA and active site mutagenized t‐PA ( K a of 6.3 × 10 6 to 8.0 × 10 6 m −1 ), but is reduced for t‐PA lacking the finger and growth factor domains ( K a of 2.0 × 10 6 m −1 ). Activation of native Glu‐plasminogen by t‐PA in the presence of proMMP‐3 obeys Michaelis–Menten kinetics; at saturating concentrations of proMMP‐3, the catalytic efficiency of two chain t‐PA is enhanced 20‐fold ( k cat / K m of 7.9 × 10 −3 vs. 4.1 × 10 −4 µ m −1 ·s −1 ). This is mainly the result of an enhanced affinity of t‐PA for its substrate ( K m of 1.6 µ m vs. 89 µ m in the absence of proMMP‐3), whereas the k cat is less affected ( k cat of 1.3 × 10 −2 vs. 3.6 × 10 −2 s −1 ). Activation of Lys‐plasminogen by two chain t‐PA is stimulated about 13‐fold at a saturating concentration of proMMP‐3, whereas that of miniplasminogen is virtually unaffected (1.4‐fold). Plasminogen activation by single chain t‐PA is stimulated about ninefold by proMMP‐3, whereas that by the mutant lacking finger and growth factor domains is stimulated only threefold. Biospecific interaction analysis revealed binding of Lys‐plasminogen to proMMP‐3 with 18‐fold higher affinity ( K a of 22 × 10 6 m −1 ) and of miniplasminogen with fivefold lower affinity ( K a of 0.26 × 10 6 m −1 ) as compared to Glu‐plasminogen ( K a of 1.2 × 10 6 m −1 ). Plasminogen and t‐PA appear to bind to different sites on proMMP‐3. These data are compatible with a model in which both plasminogen and t‐PA bind to proMMP‐3, resulting in a cyclic ternary complex in which t‐PA has an enhanced affinity for plasminogen, which may be in a Lys‐plasminogen‐like conformation. Maximal binding and stimulation require the N‐terminal finger and growth factor domains of t‐PA and the N‐terminal kringle domains of plasminogen.