N-acetyl-D-glucosaminylphosphatidylinositol de-N-acetylase from Entamoeba histolytica: metal alters catalytic rates but not substrate affinity.
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.
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India.
Mohammad
M
Ashraf
Bhawna
B
Yadav
Sreejith
S
Perinthottathil
Kokila Sree
KS
Kumar
Divya
D
Vats
Rohini
R
Muthuswami
Sneha Sudha
SS
Komath
D000818:Animals; D002384:Catalysis; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000235:genetics; D017261:Glycosylphosphatidylinositols / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008670:Metals / Q000737:chemistry* / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity / Q000502:physiology
D017261:Glycosylphosphatidylinositols; D008670:Metals; D015800:Protozoan Proteins; D006867:Hydrolases