Biochemical characterization of human collagenase-3

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• A novel matrix metalloproteinase, collagenase-3 (MMP-13), was identified from breast tumor cDNA.
• A potential role for MMP-13 in tumor progression has been proposed.
• Understanding MMP-13's function in connective tissue turnover is crucial.

Purpose of the Study:

• To express and purify recombinant human procollagenase-3.
• To biochemically characterize the enzyme's properties, activation, and substrate specificity.
• To investigate the interaction of collagenase-3 with tissue inhibitors of metalloproteinases (TIMPs).

Main Methods:

• Recombinant human procollagenase-3 was expressed and purified.
• Enzyme activation was induced using p-aminophenylmercuric acetate, stromelysin, or trypsin.
• Substrate specificity was analyzed using soluble and fibrillar collagens, gelatin, and synthetic peptide substrates.
• Inhibition studies were performed using TIMP-1, TIMP-2, and TIMP-3.

Main Results:

• Purified procollagenase-3 was glycosylated with a M(r) of 60,000.
• Activation yielded an intermediate form (M(r) 50,000) and a final active enzyme (M(r) 48,000).
• Collagenase-3 preferentially hydrolyzed soluble type II collagen and efficiently degraded gelatin and specific peptide substrates.
• Active collagenase-3 was inhibited stoichiometrically by TIMP-1, TIMP-2, and TIMP-3.

Conclusions:

• Collagenase-3 exhibits distinct substrate specificity, favoring type II collagen.
• The enzyme's activity is regulated by TIMPs, similar to other matrix metalloproteinases.
• These findings support a significant role for collagenase-3 in the in vivo turnover of connective tissue matrix constituents.