Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human skin fibroblasts, grown to confluency in the presence of 32P for random labelling of the phospholipids, showed upon 24 h incubation in the presence of either 8 mM L-serine or 4 mM ethanolamine an increased content of phosphatidylserine (150% of control cells) or phosphatidylethanolamine (116% of control cells), respectively. Concomitantly the phosphatidylcholine correspondingly decreased. Upon cell harvesting and gentle enzyme preparation the base-treated cells demonstrated a significantly higher unstimulated, fluoride- and thyrotropin-stimulated activity of adenylate cyclase. The activities of total ATPase, ouabain-sensitive ATPase, 5'-nucleotidase and gamma-glutamyltransferase remained unaltered. When subjecting enzyme preparations from fibroblasts to ultrasonication the activity of adenylate cyclase decreased progressively with energy applied, whereas the activities of the other enzymes were unaltered ((K+ + Na+)-ATPase, 5'-nucleotidase) or even increased (Mg2+-ATPase, gamma-glutamyltransferase). The results have a bearing upon the regulatory function of the phospholipid microenvironment of membrane-bound enzymes.
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PMID:The influence of changes in the phospholipid pattern of intact fibroblasts on the activities of four membrane-bound enzymes. 1 85

Several analogs of lysolecithin were found to solubilize human erythrocyte ghosts comparably or even better than other detergents. Derivatives with aliphatic chains of 12 to 14 carbons were most effective. The phosphorylcholine detergents apparently possess low protein-denaturing properties, since they, for the first time, allowed the solubilization of enzymatically active acyl-CoA:lysolecithin acyltransferase from thymocyte plasma membranes. The solubilized enzyme was not sedimented at 177,000 x g for 60 min and penetrated into Sepharose 6B gels. Low detergent concentration resulted in a selective extraction of the acyltransferase (about 70%) as compared to alkaline phosphatase, nucleotide pyrophosphatase, gamma-glutamyltransferase or Mg2+-ATPase (30 to 40%). The selectivity was reflected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of soluble and sedimentable membrane fractions; three bands of approximately 53, 84, and 94 x 10(3) daltons were enriched in the supernatants, whereas one band of about 68 x 10(3) daltons was concentrated in the pellet. The preferential extraction of acyltransferase may be related to particularly high affinity of lysolecithin analogs for this enzyme, which at higher concentrations was competitively inhibited by these detergents. The inhibitor constants ranged from 1400 micron for the C10 analog (ET-10-H) to 80 micron for the compound with 16 carbons (ET-16-H) per aliphatic chain.
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PMID:Detergent properties of water-soluble choline phosphatides. Selective solubilization of acyl-CoA:lysolecithin acyltransferase from thymocyte plasma membranes. 42 75

Progressive familial intrahepatic cholestasis type 1 is a rare genetic liver disease that presents in the first year of life. Bile salts are elevated and these patients are often jaundiced. Despite the cholestasis, serum gamma-glutamyltransferase activity is normal or reduced. Pruritus is a major symptom in these patients. Partial external biliary diversion is helpful in several patients as it reduces the pruritus and postpones or even avoids liver transplantation. The disease is caused by mutations in the gene ATP8B1 that preclude the normal expression of ATP8B1. ATP8B1 is a protein that acts as a lipid flippase, transporting phosphatidylserine from the exoplasmic to the cytoplasmic leaflet of the canalicular membrane of hepatocytes. The authors have shown that the canalicular membrane of ATP8B1-deficient hepatocytes is less stable as evidenced by enhanced extraction of membrane constituents by bile salts. Recent evidence suggests membrane instability in ATP8B1-deficient hair cells of the ear, providing an explanation for hearing loss in ATP8B1 deficiency. Although the exact etiology of cholestasis is incompletely understood, it is hypothesized that ATP8B1 deficiency results in enhanced cholesterol extraction from the canalicular membrane, which impairs the function of the bile salt export pump (BSEP), resulting in cholestasis. Mutations in ATP8B1 also cause benign recurrent intrahepatic cholestasis, a milder variant of the disease characterized by episodes of cholestasis. The onset and resolution of the cholestatic episodes in these patients is still not well understood.
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PMID:Progressive familial intrahepatic cholestasis type 1. 2042 94