Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peritoneal macrophages were obtained from untreated mice and from mice treated with thioglycollate medium (TA), proteose peptone medium (PP), or a suspension of streptococcus A cell wall material (SA). The biochemical and secretory properties of these cells in long term cultures (up to 2 wk) were compared. TA-elicited macrophages contained more protein, lactate dehydrogenase, lysosomal hydrolases, and in particular, more plasminogen activator than the other cells studied. All types of macrophages studied were found to release considerable amounts of lysosomal hydrolases (beta-glucuronidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and acid phosphatase) into the medium. Release was independent of phagocytosis and must, therefore, be regarded as true secretion. In both elicited and nonelicited macrophages, the rates of lysosomal enzyme secretion were virtually identical in the presence and in the absence of serum, and they were not enhanced by increasing serum concentrations. Lysosomal enzyme secretion in macrophages appears to depend on protein synthesis, since it was blocked by low concentrations of cycloheximide which neither affected cell viability nor lowered the intracellular enzyme levels. The amounts of lysosomal hydrolases secreted were highest in TA-elicited macrophages. The rates of secretion of PP- or SA-elicited and of nonelicited macrophages were about one-fourth of that of the TA-elicited cells. This difference, although significant, is much smaller than that observed for the secretion of plasminogen activator which was 20-50 times higher in TA-elicited cells. Acid glycosidases were also found in the peritoneal lavage media used for cell harvesting from both treated and nontreated mice. This indicates that active secretion of lysosomal hydrolases may be an in vivo property of the macrophage.
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PMID:Secretion of lysosomal hydrolases by stimulated and nonstimulated macrophages. 2 35

The elimination of native and carbohydrate-modified tissue type plasminogen activator (t-PA) after an i.v. bolus injection was studied in rabbits. t-PA with a low content of mannose (man-t-PA) was obtained by treatment with alpha-mannosidase, which cleaves terminal mannose from the carbohydrate side chains of the molecule. About 50% of the total mannose was removed from the native t-PA. Clearance of t-PA in rabbits was followed by measurements of both the fibrinolytic activity of the activators and the radioactivity of the iodine-labelled compounds. A biphasic mode of elimination of the fibrinolytic activity as well as the radioactivity was found with both the native and the carbohydrate modified t-PA. The initial half-life (t 1/2 alpha) was the same, about 1.5 minutes, for both compounds, irrespective of method of analysis. The late half-life (t 1/2 beta) was also the same, about 15 minutes, for both compounds. However, the beta-elimination of native t-PA could only be determined accurately from radioactivity data in the dosages tested, i.e. up to 2 mg of t-PA. No dose dependency in the elimination pattern was observed. In gel filtration experiments, with plasma from the rabbits, it was demonstrated that in addition to fibrinolytically active t-PA and man-t-PA, both fibrinolytically inactive high molecular weight complexes and low molecular weight degradation products of the activators were present in plasma after injection of the compounds. The second phase of elimination (beta) was much more pronounced after mannosidase treatment of the t-PA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Elimination of native and carbohydrate-modified tissue plasminogen activator in rabbits. 251 4

When messenger RNA (mRNA) from both untreated and phorbol ester-treated melanoma cells is translated in simple reticulocyte lysates, tissue-type plasminogen activator can be immunoprecipitated by an affinity-purified antibody as a approximately 52,000 mol wt protein, with no detectable biological (plasminogen activating) activity. When the reticulocyte lysate system is supplemented with a preparation of microsomal membranes, biological activity becomes detectable and a 63,000 mol wt protein can be immunoprecipitated with the same antibody. Furthermore, when natural tissue-type plasminogen activator (mol wt approximately equal to 70,000) is incubated with different glycosidases, distinct alterations in the electrophoretic mobility of the molecules are observed, together with alterations in the level of biological activity. While treatment with neuraminidase and beta-galactosidase caused decreases in activity, alpha-mannosidase caused an increase. These results suggest that the carbohydrate part of the molecule can influence its biological behavior.
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PMID:Influence of carbohydrate side chains on activity of tissue-type plasminogen activator. 308 8