Mapping the heparin-binding domain of human hepatic lipase.
Human hepatic lipase (HL) is known to bind to the cell surface of hepatocytes and the sinusoidal endothelium of the liver. In each case, it appears that the enzyme remains associated with the cell surface through an ionic interaction with heparan sulfate proteoglycans. However, it remains unclear as to which residues are responsible for this critical function of the enzyme. In the present study, we have used a systematic approach to map the heparin-binding regions of human HL by utilizing peptide arrays spanning the complete sequence of the mature protein. Following probing with biotin-heparin, six peptides spanning residues 301-320 and 465-476 were identified as regions binding to heparin. Probing of an additional array containing these six parent peptides and a comprehensive series of mutant peptides identified two putative HL heparin-binding domains. The first was composed of residues R310, K312, K314, and R315 at the distal N-terminal domain and the second was composed of residues R473, K474, and R476 at the C-terminal end of the protein.
James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, and Healthy Heart Program, St. Paul's Hospital, Department of Pathology and Laboratory Medicine, and The University of British Columbia, Vancouver, BC, Canada.
Willie
W
Yu
John S
JS
Hill
D000595:Amino Acid Sequence; D001665:Binding Sites; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D008049:Lipase / Q000032:analysis* / Q000737:chemistry*; D008969:Molecular Sequence Data; D019151:Peptide Library; D010449:Peptide Mapping; D040081:Protein Array Analysis; D011485:Protein Binding; D020539:Sequence Analysis, Protein
C504173:LIPC protein, human; D019151:Peptide Library; D006493:Heparin; D008049:Lipase