Human ADAM 12 (Meltrin α) Is an Active Metalloprotease

• Published in: The Journal of biological chemistry 1998-07, Vol.273 (27), p.16993-16997
• Main Authors: Loechel, F, Gilpin, B J, Engvall, E, Albrechtsen, R, Wewer, U M
• Format: Article
• Language: English
• Subjects: ADAM Proteins; ADAM12 Protein; Amino Acid Sequence; Animals; COS Cells; Cysteine - chemistry; Disintegrins - chemistry; Disintegrins - genetics; Disintegrins - metabolism; Humans; Hydrolysis; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Metalloendopeptidases - chemistry; Metalloendopeptidases - genetics; Metalloendopeptidases - metabolism; Molecular Sequence Data; Mutagenesis, Site-Directed; Sequence Homology, Amino Acid
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.27.16993

The ADAMs ( a d isintegrin a nd m etalloprotease) are a family of multidomain proteins with structural homology to snake venom metalloproteases. We recently described the cloning and sequencing of human ADAM 12 (meltrin α). In this report we provide evidence that the metalloprotease domain of ADAM 12 is catalytically active. We used the trapping mechanism of α 2 -macroglobulin to assay for protease activity of wild-type and mutant ADAM 12 proteins produced in a COS cell transfection system. We found that ADAM 12 is synthesized as a zymogen, with the prodomain maintaining the metalloprotease in a latent form, probably by means of a cysteine switch. The zymogen could be activated chemically by alkylation with N -ethylmaleimide. Cleavage of the prodomain at a site for a furin-like endopeptidase resulted in an ADAM 12 protein with proteolytic activity. The protease activity was sensitive to inhibition by 1,10-phenanthroline and could be eliminated by mutation of the critical glutamate residue at the active site. The demonstration that the ADAM 12 metalloprotease domain is functional may have important implications for future studies that explore the role of ADAM 12 protein in development and disease.