title: Amino acid sequence of the active site of human pseudocholinesterase.
abstract: The usual E1u and atypical E1a human pseudocholinesterases (acylcholine acylhydrolase, EC 3.1.1.8) were purified to homogeneity. The active-site serine residue was conjugated with diisopropyl fluorophosphate and digested with trypsin. The tryptic peptide containing the active site was isolated by gel filtration followed by two-dimensional paper chromatography and electrophoresis. The amino acid sequence of the active site peptide obtained from the usual E1u enzyme was found to be Gly-Glu-Ser-Ala-Gly-Ala-Ser-Ala-Val-Ser-Leu. A remarkable structural homology exists between the human and the horse enzymes in their active sites. From the difference in electrophoretic mobility of the active-site peptides obtained from the usual and atypical enzymes, the probable structure of the atypical human enzyme was deduced as Gly-His-Ser-Ala-Gly-Ala-Ser-Ala-Val-Ser-Leu.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002091:Butyrylcholinesterase / Q000097:blood / Q000235:genetics* / Q000302:isolation & purification; D002802:Cholinesterases / Q000235:genetics*; D014644:Genetic Variation; D006720:Homozygote; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis
chemical_list: D010446:Peptide Fragments; D002091:Butyrylcholinesterase; D002802:Cholinesterases