This 1996 lab study made and purified human collagenase-3 (MMP13) and tested what it cuts. It broke down soluble type II collagen in preference to types I and III, which it cut five or six times less efficiently. It also broke down gelatin, and TIMP-1, TIMP-2 and TIMP-3 each blocked it one to one.
Researchers expressed and purified recombinant human procollagenase-3, the inactive form of MMP13. They activated it with a chemical (APMA), with stromelysin or with trypsin, and read the sequence at the start of each form. They then tested the active enzyme against soluble type I, II and III collagen, fibrillar type I collagen, gelatin and two peptide substrates, and against the inhibitors TIMP-1, TIMP-2 and TIMP-3.
The proenzyme was glycosylated, with a molecular mass of about 60,000. Activation passed through a 50,000 intermediate to a final active enzyme of 48,000. Trypsin activation quickly cut off the enzyme's C-terminal domain, and its collagen-cutting activity fell. The active enzyme cut soluble type II collagen preferentially and was five or six times less efficient on types I and III. On fibrillar type I collagen it was about as efficient as MMP-1 and MMP-8. Unlike those two, it also broke down gelatin and the peptides efficiently. TIMP-1, TIMP-2 and TIMP-3 each inhibited it one molecule to one.
This is purified enzyme in a test tube, not cartilage. It shows what MMP13 is able to cut and how it compares across substrates, not what it actually cuts in a joint, where inhibitors, other enzymes and the structure of the tissue all play a part. The study did not look at cartilage cells, animals or people.
It helps explain why MMP13 matters so much in cartilage. It prefers type II collagen, the cartilage collagen, and it can also break down gelatin, the unwound collagen left after the first cut. It also shows that the body's own inhibitors, the TIMPs, can switch it off.
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...
In two main ways. Cells release MMP13 as an inactive proenzyme that must be cut before it works, and the body makes its own inhibitors, the TIMPs. TIMP-1, TIMP-2 and...
Yes. Besides type II collagen, MMP13 cuts aggrecan, the water-holding molecule in cartilage, at two sites, one of them not seen with other enzymes. Purified MMP13 also...
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...