| Literature References | 1. CHAPUS, C., ROVERY, M., SARDA, L. AND VERGER, R.
Minireview on pancreatic lipase and colipase.
BIOCHIMIE 70 1223-1234 (1988).
2. PERSSON, B., BENGTSSON-OLIVECRONA, G., ENERBACK, S., OLIVECRONA, T.
AND JOERNVALL, H.
Structural features of lipoprotein-lipase - lipase family relationships,
binding interactions, non-equivalence of lipase cofactors, vitellogenin
similarities and functional subdivision of lipoprotein-lipase.
EUR.J.BIOCHEMISTRY 179 39-45 (1989).
3. HEGELE, R.A., TU, L. AND CONNELLY, P.W.
Human hepatic lipase mutations and polymorphisms.
HUM.MUTAT. 1 320-324 (1992).
4. CAI, S.J., WONG, D.M., CHEN, S.H. AND CHAN, L.
Structure of the human hepatic triglyceride lipase gene.
BIOCHEMISTRY 28 8966-8971 (1989).
5. WION, K.L., KIRCHGESSNER, T.G., LUSIS, A.J., SCHOTZ, M.C. AND LAWN, R.M.
Human lipoprotein lipase complementary DNA sequence.
SCIENCE 235 1638-1641 (1987).
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| Documentation | Triglyceride lipases (EC 3.1.1.3) are lipolytic enzymes that hydrolyse
ester linkages of triglycerides [1]. Lipases are widely distributed in
animals, plants and prokaryotes. At least three tissue-specific isozymes
exist in higher vertebrates: pancreatic, hepatic and gastric/lingual. These
lipases are closely related to each other and to lipoprotein lipase
(EC 3.1.1.34), which hydrolyses triglycerides of chylomicrons and very
low density lipoproteins (VLDL) [2].
Familial human hepatic lipase deficiency is a rare recessive disorder that
results from mutation in position 405 of the mature protein. The disease is
characterised by premature atherosclerosis and abnormal circulating
lipoproteins [3].
The structure of the human hepatic triglyceride lipase gene has been
determined [4]. The hepatic lipase gene spans ~60 kb, and contains 8 introns
and 9 exons: exon 1 encodes the signal peptide; exon 4, a region that binds
to the lipoprotein substrate; exon 5, an evolutionarily highly-conserved
region of potential catalytic function; and exons 6 and 9 encode sequences
rich in basic amino acids, thought to be important in anchoring the enzyme
to the endothelial surface by interacting with acidic domains of surface
glycosaminoglycans [4]. The human lipoprotein lipase gene has an identical
exon-intron organisation, with analogous structural domains, supporting the
common evolutionary origin of these two lipolytic enzymes [5].
HEPLIPASE is a 9-element fingerprint that provides a signature for hepatic
triacylglycerol lipases. The fingerprint was derived from an initial
alignment of 4 sequences: the motifs were drawn from conserved sections
spanning the full alignment length, focusing on those regions that
characterise the hepatic lipases but distinguish them from the rest of the
lipase family - motif 5 lies in a potential heparin binding domain. A single
iteration on OWL30.0 was required to reach convergence, no further sequences
being identified beyond the starting set.
An update on SPTR37_9f identified a true set of 5 sequences.
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