Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Purified plasma membranes were obtained from five transplantable human tumors, a grade IV astrocytoma, an oat cell carcinoma, and three melanomas. Plasma membrane fractions were isolated from tumor homogenates by differential and discontinuous sucrose gradient centrifugation. Determination of enzyme activities indicated that the plasma membranes were enriched 10- to 20-fold with respect to 5'-nucleotidase, nicotinamide adenine dinucleotide glycohydrolase, Mg2+-activated nucleoside triphosphatase, and sialic acid. Specific activities of nearly all the enzymes varied with the individual tumors, even among tumors of the same type, i.e., the melanomas. Electron micrographs of the plasma membrane fractions showed smooth single-membrane vesicles with slight contamination by lysosomes. Therefore, these membranes are suitable for comparative biochemical studies and for the preparation of tumor-specific monoclonal antibodies. Plasma membranes from all five tumors contained very high Mg2+-adenosine triphosphatase (ATPase) activities. The Na+-K+-ATPase was a minor component of the total ATPase of these membranes (less than 30%). The major component was an ATPase exhibiting similar activity toward several nucleoside triphosphates. The activity of such a nucleoside triphosphatase has been correlated with tumorigenicity in cultured liver epithelial cells. The nucleoside triphosphatase of the plasma membranes of astrocytoma and oat cell carcinoma was stimulated from 50 to 1005 by concanavalin A, whereas ATPase of the melanoma plasma membranes was not or only slightly stimulated. The different response to concanavalin A could be due to differences in the ATPase molecules of the individual tumors or to the different environment of the ATPase.
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PMID:Isolation and characterization of plasma membranes from transplantable human astrocytoma, oat cell carcinoma, and melanomas. 611 38

Salmonella Typhimurium is a common cause of gastroenteritis in humans and also localizes to neoplastic tumors in animals. Invasion of specific eukaryotic cells is a key mechanism of Salmonella interactions with host tissues. Early stages of gastrointestinal cell invasion are mediated by a Salmonella type III secretion system, powered by the adenosine triphosphatase invC. The aim of this work was to characterize the invC dependence of invasion kinetics into disparate eukaryotic cells traditionally used as models of gut epithelium or neoplasms. Thus, a nondestructive real-time assay was developed to report eukaryotic cell invasion kinetics using lux+ Salmonella that contain chromosomally integrated luxCDABE genes. Bioluminescence-based invasion assays using lux+ Salmonella exhibited inoculum dose-response correlation, distinguished invasion-competent from invasion-incompetent Salmonella, and discriminated relative Salmonella invasiveness in accordance with environmental conditions that induce invasion gene expression. In standard gentamicin protection assays, bioluminescence from lux+ Salmonella correlated with recovery of colony-forming units of internalized bacteria and could be visualized by bioluminescence microscopy. Furthermore, this assay distinguished invasion-competent from invasion-incompetent bacteria independent of gentamicin treatment in real time. Bioluminescence reported Salmonella invasion of disparate eukaryotic cell lines, including neoplastic melanoma, colon adenocarcinoma, and glioma cell lines used in animal models of malignancy. In each case, Salmonella invasion of eukaryotic cells was invC dependent.
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PMID:Stably integrated luxCDABE for assessment of Salmonella invasion kinetics. 1912 92