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phospholipase B1; membrane-associated; phospholipase B, hPLB; phospholipase B/lipase; PLB/LIP [includes: phospholipase A2; Lysophospholipase] (PLB1, PLB)
Function:
- membrane-associated phospholipase
- Ca+2-independent broad substrate specificity including phospholipase A2/lysophospholipase activity
- preferential hydrolysis at the sn-2 position of diacylphospholipids & diacyglycerol, whereas it shows no positional specificity toward triacylglycerol
- esterase activity toward p-nitrophenyl
- may act on the brush border membrane to facilitate absorption of digested lipids
- undergoes proteolytic cleavage in the ileum (putative)
2-lysophosphatidylcholine + H2O
glycerophosphocholine + a carboxylate
phosphatidylcholine + H2O
1-acylglycerophosphocholine + a carboxylate
Inhibition:
- inhibited by diisopropyl fluorophosphate
Structure:
- repeat 2 contains the catalytic domain (putative)
- belongs to the 'GDSL' lipolytic enzyme family phospholipase B1 subfamily
Compartment:
- apical cell membrane
- present in the intestinal brush border membranes (putative)
Alternative splicing: named isoforms=5
Expression:
- expressed in the epidermis (at protein level)
General
glycoprotein
membrane protein
phospholipase B
Properties
SIZE: entity length = 1458 aa
MW = 163 kD
COMPARTMENT: cellular membrane
MOTIF: signal sequence {1-21}
4 X 308-326 AA approximate repeats {39-1402}
MOTIF: 1 {39-347}
N-glycosylation site {N240}
2 {362-707}
serine residue {S400}
binding site
SITE: 474-474
FOR-BINDING-OF: Substrate; via amide nitrogen
N-glycosylation site {N493}
binding site
SITE: 513-513
FOR-BINDING-OF: Substrate
N-glycosylation site {N529}
3 {708-1054}
N-glycosylation site {N797}
histidine residue {H1002}
N-glycosylation site {N1055}
4 {1064-1402}
Necessary for membrane localization {1403-1445}
MOTIF: transmembrane domain {1418-1438}
Database Correlations
UniProt Q6P1J6
Pfam PF00657
References
UniProt :accession Q6P1J6