Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.2.7 (heparinase)
 1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heparin binding growth factors (HBGF), a major component of retinal endothelial cell growth factor activity, have been located particularly to a storage site in the vascular basement membrane, where they are bound to heparan sulphate in a relatively inactive state. It has been suggested that angiogenic activity in the retina may be released, during basement membrane degradation, by heparinase enzymes. We now report that mitogenic saline extracts of retina contain heparinase-like activity, whereas non-mitogenic retinal homogenate does not. However, heparinase-like activity may only account for part of the mitogenic activity in retinal extract. In previous studies we have shown that the absence of mitogenic activity in retinal homogenate is due to a heat-labile inhibitor. Heat-treatment of retinal homogenate is due to a heat-labile inhibitor. Heat-treatment of retinal homogenate restored mitogenic activity to 60% of that in retinal extract, but this heat-treated homogenate still lacked heparinase activity.
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PMID:Retina contains endogenous heparinase activity. 273 12

Matrix production by smooth muscle cells (SMC) appears to play a major role in the intimal thickening process. Proteoglycans (PG) are the predominant extracellular matrix component of early restenotic lesions. As angiotensin II (A II) has been proposed as a mediator of restenotic process, we hypothesized that A II may directly affect PG synthesis by SMC. SMC were cultured in the presence of [35S]sulfate and angiotensin II, and both the secreted and membrane-bound proteoglycans were analyzed. A II (1 to 100 nM) evoked a dose- and time-dependent increase in both cell- and media-associated PG production, an effect abrogated by the A II receptor antagonist, saralasin. SMC constitutively synthesize small amounts of PG with a molecular mass of 170-250 kDa. After treatment with A II, the abundance of PG is increased, as well as its molecular mass (230-300 kDa). Selective degradation by chondroitinases and heparinase identified chondroitin and dermatan sulfate PG as the predominant form being induced. These results demonstrate that the effect of A II is not general and is specific to certain classes of PGs. In order to further examine the specificity of the A II effect, we compared the synthesis of PG induced by A II with that induced by platelet-derived growth factors AA and BB (PDGF-AA and -BB), insulin-like growth factor I (IGF-I), and tumor necrosis factor alpha (TNF alpha). This comparison demonstrated that the profile of PG induced by A II is different from the other factors examined. Taken together, these data indicate that A II may not only function as a hypertrophic factor for SMC, but in addition may also be a potent modulator of specific PG synthesis by these same cells, which could significantly contribute to the formation of atherosclerotic and restenotic lesions.
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PMID:Stimulation of rat vascular smooth muscle cell glycosaminoglycan production by angiotensin II. 784 Aug 14