Human milk bile-salt stimulated lipase. Sequence similarity with rat lysophospholipase and homology with the active site region of cholinesterases.
To determine the active site residue, human milk bile-salt stimulated lipase (BSSL) was labelled with [3H]diisopropyl fluorophosphate (DFP). Partial sequence analysis of cyanogen bromide fragments (a total of 146 residues from 6 peptides) revealed 84% sequence identity with a putative rat lysophospholipase. Sequence analysis of a [3H]DFP-labelled peptide indicated that the active site serine was contained in the sequence Gly-Glu-Ser-Ala-Gly. In addition to similarity with rat lysophospholipase, this sequence showed homology with regions of human butyrylcholinesterase and electric ray acetylcholinesterase (68% identity). It is concluded that these proteins are members of a new supergene family.
Christie
D L
DL
Department of Biochemistry, University of Auckland, New Zealand.
Cleverly
D R
DR
O'Connor
C J
CJ
D000110:Acetylcholinesterase / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001647:Bile Acids and Salts / Q000494:pharmacology; D002091:Butyrylcholinesterase / Q000737:chemistry; D004789:Enzyme Activation; D006801:Humans; D008049:Lipase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D008245:Lysophospholipase / Q000737:chemistry; D008892:Milk / Q000201:enzymology*; D008969:Molecular Sequence Data; D009943:Organophosphorus Compounds / Q000737:chemistry; D051381:Rats
D001647:Bile Acids and Salts; D009943:Organophosphorus Compounds; C002226:diisopropylphosphate; D008049:Lipase; D008245:Lysophospholipase; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase