This 1994 lab study cloned the gene for a new human matrix metalloproteinase from a breast tumour library and named it collagenase-3, the third collagenase known. The protein it coded for could break down fibrillar collagens. The team found its genetic message in breast tumours but not in the normal tissues they tested.
The researchers screened a library of genetic material (cDNA) made from a human breast tumour and found the sequence of an unknown member of the matrix metalloproteinase family. They read the sequence, compared it with the MMPs already known, and made the protein in a vaccinia virus system to see what it could cut. They then looked for its messenger RNA in breast tumours and in a range of other human tissues.
The sequence coded for a protein of 471 amino acids with the hallmarks of the MMP family, including the zinc-binding site and the stretch that keeps the enzyme inactive until needed. It also carried residues specific to the collagenase subfamily. Because it was the third collagenase known, after the fibroblast and neutrophil collagenases, the team named it collagenase-3. The recombinant protein broke down fibrillar collagens. Its messenger RNA turned up in breast tumours, in three forms, but not in normal breast, benign breast lumps (fibroadenomas), liver, placenta, ovary, uterus, prostate or parotid gland.
This paper does not look at cartilage or joints at all. The tissue survey covered breast and a handful of other organs, so it cannot say where else in the body the enzyme is made. The link between collagenase-3 and cartilage came two years later, from other groups. The suggested role in tumours was a proposal based on where the enzyme appeared, not a test of what it does there.
This is where the name comes from. Collagenase-3 is the same enzyme researchers now call MMP13. Every later study of MMP13 in cartilage builds on the sequence first described here, and the finding that it could cut fibrillar collagen was the first sign of what it might do in a joint.
MMP13, short for matrix metalloproteinase-13 and also called collagenase-3, is an enzyme that cuts collagen. Cartilage cells make it, and of the collagen-cutting enzymes...
Both are collagenases, enzymes that can cut intact collagen, and they cut type II collagen at the same bond. MMP13 is much faster at it: at least ten times faster than...