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)

Hormonal regulation of L-serine dehydratase [L-serine hydro-lyase (deaminating), EC 4.2.1.13] was studied in primary cultures of adult-rat hepatocytes. The hepatocytes were isolated by collagenase perfusion and maintained in culture on collagen-gel/nylon-mesh substrata. L-Serine dehydratase activity was measured with [14C]threonine as substrate. The enzyme activity in hepatocytes of normal adult rats was low and declined rapidly in culture in L-15 medium containing 0.1 micro M-insulin and even more in the presence of glucose. L-Serine dehydratase activity in hepatocytes of rats with streptozotocin-induced diabetes was initially 20-fold higher than that of normal rats, but fell rapidly to a low value by 4 days in culture. Hormonal regulation of the enzyme activity was manifested by treatment of the cultured hepatocytes with insulin (0.1 micro M), glucagon (0.3 micro M), dexamethasone (10 micro M) and combinations of these hormones. Either glucagon or dexamethasone in the absence of insulin enhanced the activity of L-serine dehydratase, but failed to do so in the presence of insulin. Treatment with both hormones resulted in a 2-3-fold increase in enzyme activity in culture on days 3 and 4. Under conditions in which the enzyme activity was enhanced, glucose production by the cultured hepatocytes was concomitantly increased. Glucose production resulted in part from gluconeogenesis from pyruvate and not entirely from glycogenolysis. The gluconeogenic conditions of culture resulted in a decrease in cellular lipids in the cultured hepatocytes, as evidenced by ultrastructural studies.
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PMID:Increase of L-serine dehydratase activity under gluconeogenic conditions in adult-rat hepatocytes cultured on collagen gel/nylon mesh. 732 17

The purification by affinity chromatography of beta-galactosidase from strains carrying sdaA/lacZ gene fusions results in the copurification of L-serine deaminase 1. We conclude that sdaA is the structural gene for the latter enzyme. The purified L-serine deaminase 1 obtained after collagenase treatment of an sdaA-collagen-lacZ fusion differs from the native enzyme by the addition of several amino acids at the C-terminal. Like the enzyme in crude extracts, this purified enzyme is catalytically inactive, and is activated by incubation with iron and dithiothreitol.
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PMID:Use of gene fusions of the structural gene sdaA to purify L-serine deaminase 1 from Escherichia coli K-12. 843 13