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)

The influence of the mode of preparation upon some of the characteristics of white adipose tissue plasma membranes and microsomes has been reported. Plasma membrane fractions prepared from mitochondrial pellet were shown to have higher specific activities of (Mg2+ + Na+ + K+)-ATPase than plasma membranes originating in crude microsomes. Isolation of fat cells by collagenase treatment was found to result in a decrease in specific activity of the plasma membrane enzymes; in plasma membranes prepared from isolated fat cells, the specific activity values obtained for (Mg2+ + Na+ +k+)-ATPase and 5'-nucleotidase were only 42% and 6.3% respectively of those obtained in plasma membranes prepared from whole adipose tissue. Purification of whole adipose tissue crude microsomes by hypotonic treatment caused extensive solubilization of the endoplasmic reticulum marker enzymes, NADH oxidase and NADPH cytochrome c reductase. The lability of endoplasmic reticulum marker enzymes, however, was found to be greatly diminished in the preparations from isolated fat cells. The possibility that NADH oxidase and NADPH cytochrome c reductase activities found in the plasma membranes are microsomal enzymes adsorbed by the plasma membranes is discussed. The peptide patterns as well as the NADH oxidase and NADPH cytochrome c reductase activity patterns of plasma membranes and purified microsomes were compared by means of sodium dodecyl sulfate or Triton X-100 polyacrylamide gel electrophoresis.
 ...
PMID:Comparison of plasma membranes and endoplasmic reticulum fractions obtained from whole white adipose tissue and isolated adipocytes. 12 89

Penicillin pretreatment enhanced the rate of PAH uptake into separated proximal tubules (collagenase digestion) from 2-week New Zealand white rabbits. A double reciprocal plot of these data suggests that penicillin increases the maximal velocity of PAH uptake. Na, K-ATPase was less in adult tissue but was unaffected by penicillin. No ultrastructural changes could be attributed to the treatment. Thus substrate stimulation of PAH transport does not involve Na, K-ATPase and probably involves soluble, rather than structural proteins.
 ...
PMID:Biochemical and ultrastructural correlates of substrate stimulation of renal organic anion transport. 13 21

A method for primary culture of ovine myometrial cells is described. After dissection, myometrium of ewe uteri was digested in trypsin and collagenase. The cells were preplated for 1 h at 37 degrees C. The non-attached cells were grown in appropriate medium supplemented with 2% fetal calf serum. They had a doubling time of 3 days, reached confluency at 10 days and did not exhibit contact inhibition. Cultures were maintained up to 22 days. Characterization of the cells was achieved by electron microscopy, analysis of myosin in cell extracts and assessment of hormone sensitivity. The cells were found to contain myofilaments, characteristic of smooth muscle. A high content of myosin (6--13%) was demonstrated on SDS-polyacrylamide gel electrophoresis: this was confirmed by ATPase activity assay. Cells responded to estradiol stimulation by increased protein synthesis, and bound [3H]estradiol in a specific and saturable way. These results suggest that myometrial cells grown in primary culture should provide a useful model for studying the hormonal control of contractile protein synthesis.
 ...
PMID:Myometrial cells in primary culture: characterization and hormonal profile. 15 21

Crude homogenates of rat cardiac muscle were fractionated in order to examine the subcellular location of adenylate cyclase in this tissue. The fractionation procedure employed differential centrifugation of homogenized material followed by collagenase treatment, centrifugation on a discontinuous sucrose density gradient and extraction with 1 M KCl. The particulate fraction obtained by this procedure contained a high specific activity and yield of adenylate cyclase, moderate levels of mitochondria and low levels of sarcoplasmic reticulum and contractile protein as judged by marker enzyme activities. Adenylate cyclase was purified 20-fold with a 33% yield from the crude homogenate, while mitochondrial, sarcoplasmic reticulum and contractile protein yields were 5, 0.4 and 0.7% respectively. The membrane fractions prepared in this manner were examined by sodium dodecyl sulfate - gel electro phoresis. Adenylate cyclase copurfied with ouabain-sensitive (Na+ + K+)-ATPase, a plasma membrane marker enzyme, and not with Ca2+ -accumulating activity, which is associated with the sarcoplasmic reticulum. The distribution of marker enzyme activities indicates that heart adenylate cyclase is not located in the sarcoplasmic reticulum but is localized predominantly, if not exclusively, in the plasma membrane.
 ...
PMID:Subcellular location of adenylate cyclase in rat cardiac muscle. 18 59

Treatment of rat liver plasma membranes with various commercial preparations of crude collagenase from Clostridium histolyticum at concentrations as low as 1 mug/ml, resulted in activation of the adenylate cyclase system. Maximal activation occurred at 50 to 100 mug/ml of collagenase, and promoted a 2- to 3-fold increase in the basal activity as well as in the activities stimulated by catecholamines, glucagon, fluoride, or GTP. This was due to an increase in the maximal velocity of the cyclizing reaction without any increase in the affinity of the enzyme for its substrate. Treatment of plasma membranes with crude collagenase did not induce gross structural modifications as judged by electron microscopic examination. 5'-Nucleotidase activity was slightly inhibited and ATPase activity remained unaffected. The stimulatory substance was nondialyzable, thermolabile, and inhibited by both EDTA and -SH reagents, thus appearing to be a protein. The following observations suggest the effects observed were due to other protease(s) present in crude collagenase: (a) only crude collagenase was active on liver adenylate cyclase: treatment with purified collagenase from C. histolyticum or from Achromobacter iophagus gave no stimulation; (b) the stimulatory activity was irreversible since washing of the membranes after treatment was without effect; (c) crude collagenase contained no lecithinase or sphingomyelinase activity under our conditions of adenylate cyclase assay; (d) after chromatography on Sephadex G-100, the activator appeared as a peak in the 30,000-dalton region and was clearly separated from the collagenase and clostripain peaks, but coincident with elastolytic and caseinolytic activities; (e) the effect of crude collagenase could be prevented by addition of elastin in vitro and was mimicked by purified elastase from hog pancreas. It remains to be seen whether the effects observed result from an increase in the catalytic constant of adenylate cyclase, or an unmasking of new catalytic sites.
 ...
PMID:Proteolytic activation of rat liver adenylate cyclase by a contaminant of crude collagenase from Clostridium histolyticum. 19 49

Specific receptors for angiotensin II (A II) were demonstrated in membrane fractions and collagenase-dispersed cells from the zona glomerulosa of the rat adrenal gland. The equilibrium association constant (Ka) of the A II binding sites was similar in particulate fractions (2.0 +/- 0.4 (SE) X 10(9) M-1) and intact glomerulosa cells (1.8 +/- 0.3 X 10(9) M-1). Specific binding of [125I]iodo-A II was enhanced by increasing sodium concentration, and in the presence of dithiothreitol, EDTA, and EGTA. Plasma membrane fractions prepared by density gradient centrifugation showed increased binding of [125I]iodo-A II, and were correspondingly enriched in adenylate cyclase and sodium-potassium-dependent ATPase. Steroid production by collagenase-dispersed adrenal glomerulosa cells was highly responsive to A II and ACTH. Significant increases in aldosterone and corticosterone production were elicited by A II concentrations as low as 3 X 10(-11) M, equivalent to normal blood levels of A II in rats (5 X 10(-11) M). The maximum increase in aldosterone production, of 6--7 times the basal value, was obtained at 10(-9) M A II. Dispersed capsular cells were also highly sensitive to ACTH, responding to concentrations down to 3 X 10(-12) M with increased aldosterone production, reaching a maximum aldosterone response of 20-fold above the basal value. The magnitudes of the aldosterone and corticosterone responses to A II in capsular and fasciculata-reticularis cells were commensurate with the distribution of A II receptors, which were 11-fold more concentrated in capsular cells. The ability of A II to evoke aldosterone production at physiological concentrations, and the correspondence between A II binding and steroidogenesis in capsular cells, demonstrate the functional importance of A II receptor sites in the zona glomerulosa of the rat adrenal cortex.
 ...
PMID:Angiotensin II receptors and aldosterone production in rat adrenal glomerulosa cells. 21 98

In the present paper we report on an improved procedure for the preparation of free uterine cells which avoids the use of trypsin and employs very low concentration of collagenase. The cells released mechanically from the digested tissue are constantly removed from the enzyme containing medium, thus minimizing exposure to collagenase. 60%-70% of the cells which make up the intact uterus are obtained as free cells and 95% of these cells are viable for at least 15 hours at 37 degrees. Metabolic integrity was assessed by measuring the cell's ability to oxidize glucose and synthesize proteins over extended periods of time. The membrane leucine carrier protein and the membrane Na+/K+ ATPase were found to be fully functional. Electron microscopic analysis of the cells confirmed their structural integrity. Data are presented illustrating that with this system the estrogen binding protein is stable at physiological temperatures. The cells contain approximately 30,000 specific estrogen binding sites, with an apparent KA of 5--6 x 10(9) M-1. At 37 degrees 80% of the hormone receptor complexes were in the nuclear fraction, 20% in the cytoplasm. The similarity of the estrogen receptor binding parameters with those measured in the intact tissue after in vivo hormone adminsistration, together with the cells' structural and metabolic integrity make this procedure for the preparation of uterine cell suspensions in high yields particularly suitable for studies in which minimal cell injury is an essential prerequisite.
 ...
PMID:An improved procedure for the preparation of rat uterine cell suspensions. 22 Jul 54

A method is described for isolation of plasmatic membranes of rat fatty cells immediately from fatty tissue without the treatment with collagenase. Homogenization of fatty tissue was carried out in large volumes of buffered sucrose and EDTA at room temperature followed by sucrose density gradient centrifugation. The preparations obtained exhibited high specific activity of the marker enzyme of plasmatic membranes [5'-nucleotidase and K+, Na+-ATPase], as well as high ability for specific binding of insulin.
 ...
PMID:[Isolation of the plasma membranes of fat cells without using collagenase]. 22 73

A micromethod for the determination of Na-K-ATPase in discrete segments of nephrons from rabbit, rat, and mouse kidneys is described. To facilitate tubule microdissection, the kidneys were perfused with collagenase after it had been verified that collagenase had no effect on ATPase activity. Individual tubule segments were dissected under stereomicroscopic observation, exposed to a hypotonic environment followed by rapid freezing, and incubated in 1 microliter assay medium. Enzyme activity was determined by direct measurement of labeled inorganic phosphate release by the hydrolysis of [gamma-32P]ATP and was expressed as a function of tubule length. This method is technically simple enough to permit simultaneous measurement of the enzyme in large numbers of tubules and sufficiently sensitive to determine its activity in each region of the nephron. Correlation of Na-K-ATPase activity in single tubules with functional measurements obtained in the corresponding segment of the nephron with the perfused tubule or micropuncture techniques should help define the role of this enzyme in tubular ion transport.
 ...
PMID:Determination of Na-K-ATPase activity in single segments of the mammalian nephron. 22 55

We have fused full length and the carboxyl-half of human MDR1 cDNA with the E. coli lacZ gene via a collagen linker and allowed their expression in yeast Saccharomyces cerevisiae. Using antibodies against beta-galactosidase we partially purified the fusion proteins by immunoprecipitation and show here that the full length fusion protein has ATPase activity. By contrast, the fusion protein containing the carboxyl-half of P-glycoprotein did not show ATPase activity, indicating that both domains of P-glycoprotein are necessary. By treatment of the immunoprecipitated fusion protein with collagenase, P-glycoprotein was released from the beta-galactosidase moiety. The results shown here open the possibility for a large scale purification of P-glycoprotein using this site specifically cleavable fusion protein.
 ...
PMID:Production of a site specifically cleavable P-glycoprotein-beta-galactosidase fusion protein. 136 54


1 2 3 4 5 6 7 8 Next >>