Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several small collagenous apatite binding (SCAB) proteins have been extracted from the mineralized matrix of fetal porcine calvarial bone. One protein (SCAB 3), released on demineralization of bone with 0.5 M EDTA, appears to represent the alpha 1 pN-propeptide that is normally released during proteolytic processing of type I procollagen. The 28 Kd protein, which stains blue with "Stains-all", is reduced to a 19 Kd fragment by bacterial collagenase digestion, but is not susceptible to cyanogen bromide. The amino acid composition, blocked amino-terminus and immunological properties are all consistent with properties of alpha 1 (I) pN-propeptide. Fractionation on hydroxylapatite in the presence of urea has revealed a nonbinding (SCAB 3a) and a binding (SCAB 3b) form. Extraction of the demineralized matrix of bone with 4 M GuHCl revealed a third form (G2-28) which was similar to SCAB 3a on hydroxylapatite chromatography but showed differences on FPLC "Mono Q" resin. The occurrence of these different forms of pN-propeptide in bone may be of significance in collagen fibril-associated hydroxylapatite formation and in the regulation of osteoblastic function during bone resorption.
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PMID:Identification of small collagenous proteins with properties of procollagen alpha 1 (I) pN-propeptide in fetal porcine calvarial bone. 339 4

Osteoclasts resorb the extracellular matrix of bone by secreting enzymes and acid into a sealed-off compartment that they form upon attachment to the bone surface. Although the lysosomal cysteine proteinases can degrade collagen after the demineralization of bone at low pH, several lines of evidence suggest that collagenase (matrix metalloproteinase-1, EC 3.4.24.7) may also be involved in this process. The question of whether collagenase is present in the osteoclast and/or in the bone-resorbing compartment has however not been resolved. We have prepared an anti-mouse collagenase antiserum and affinity-purified an IgG fraction that specifically immunoblots and immunoprecipitates (pro)collagenase. Using these antibodies, we demonstrate by immunolocalization the presence of (pro)collagenase both in the osteoclasts and in the extracellular subosteoclastic bone-resorbing compartment. These specific localizations were observed not only in mice but also in rat and rabbit osteoclasts and using not only the antibody we have prepared but also antibodies raised in other laboratories against rat (Jeffrey et al., J. Cell. Physiol. 143, 396-403, 1990) and rabbit (Brinckerhoff et al., J. Biol. Chem. 265, 22262-22269, 1990) collagenase. Intracellular collagenase was observed in the osteoclasts whether the cells were plated on bone or cultured on glass coverslips. It is proposed that osteoclastic collagenase is secreted in the resorbing compartment where it may cooperate with the lysosomal cysteine proteinases in the degradation of the collagen component of the matrix during the resorption of bone.
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PMID:(Pro)collagenase (matrix metalloproteinase-1) is present in rodent osteoclasts and in the underlying bone-resorbing compartment. 812 92