Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been suggested previously that small amounts of the mature 115-kDa form of phosphatidylinositol (PtdIns)-glycan-specific phospholipase D from bovine serum may exist as a 47-kDa form which can also be generated in vitro by treatment with proteases. In this study, we investigated the possible proteolytic processing by trypsin of partially purified PtdIns-glycan- specific phospholipase D from bovine serum and found that tryptic digestion caused an apparent activation of the enzyme when assayed in the presence of 0.1% (mass/vol.) Triton X-100. Trypsin cleaved the 115-kDa form of PtdIns-glycan-specific phospholipase D into three major polypeptides with molecular masses of 33, 39, and 47 kDa. Under non-denaturing conditions, the polypeptides remained tightly but noncovalently associated with each other. However, in the presence of 6 M urea, the polypeptides could be separated by anion-exchange chromatography. After renaturation, PtdIns-glycan-specific phospholipase D activity was found to be associated with a 39-kDa fragment. Based on its size and its amino acid sequence, the active-site-containing fragment consisted of approximately 275 residues of the N-terminal region of PtdIns-glycan-specific phospholipase D. The active 39-kDa fragment hydrolyzed the PtdIns-glycan-anchors of solubilized acetylcholinesterase from bovine erythrocytes and variant surface glycoprotein from blood stream trypanosomes. However, this fragment was inactive on membrane-associated acetylcholinesterase and PtdIns.
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PMID:Generation by limited proteolysis of a catalytically active 39-kDa protein from the 115-kDa form of phosphatidylinositol-glycan-specific phospholipase D from bovine serum. 792 7

Several mammalian enzymes are anchored to the outer surface of the plasma membrane by a covalently attached glycosylphosphatidylinositol (GPI) structure. These include acetylcholinesterase, alkaline phosphatase (AP) and 5'-nucleotidase among other enzymes. Recently, it has been reported that these membrane enzymes can be released into the serum by the GPI-dependent phospholipase D under various medical disturbances such as cancer and/or by chemical and physical manipulation of the biological systems. Treatment of MCF-7 cells with two consecutive effective concentrations of 3-hydrogenkwadaphnin (3-HK, 3 nM) for 48 h enhanced membrane AP activity by almost 330% along with a 40% reduction in the AP activity of the cell culture medium. In addition, our data indicate that 3-HK is capable of inducing mainly the tissue-nonspecific alkaline phosphatase (TNAP) isoenzyme, along with enhancing its thermostability. These findings, besides establishing a correlation between the antiproliferative activity of 3-HK and the extent of plasma membrane AP activity, might assist in the development of new diagnostic tools for following cancer medical treatments.
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PMID:Plasma membrane homing of tissue nonspecific alkaline phosphatase under the influence of 3-hydrogenkwadaphnin, an antiproliferative agent from Dendrostellera lessertii. 1752 90


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