Abstract
PIG-L/GPI12 proteins are endoplasmic reticulum-resident membrane proteins involved in the second step of glycosylphosphatidylinositol anchor biosynthesis in eukaryotes. We show that the Entamoeba histolytica PIG-L protein is optimally active in the acidic pH range. The enzyme has an intrinsic low level of de-N-acetylase activity in the absence of metal and is significantly stimulated by divalent cations. Metal binding induces a large conformational change in the protein that appears to improve catalytic rates while not altering the affinity of the enzyme for its substrate.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Catalysis
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Entamoeba histolytica / enzymology*
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Entamoeba histolytica / genetics
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Glycosylphosphatidylinositols / chemistry*
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Glycosylphosphatidylinositols / genetics
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Glycosylphosphatidylinositols / metabolism
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Hydrogen-Ion Concentration
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Hydrolases / chemistry*
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Hydrolases / genetics
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Hydrolases / metabolism
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Metals / chemistry*
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Metals / metabolism
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Protozoan Proteins / chemistry*
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Protozoan Proteins / genetics
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Protozoan Proteins / metabolism
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Substrate Specificity / physiology
Substances
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Glycosylphosphatidylinositols
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Metals
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Protozoan Proteins
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Hydrolases