Effects of substitutions of glycine and asparagine for serine132 on activity and binding of human lipoprotein lipase to very low density lipoproteins

[摘要]

For studying the role of Ser¹³² in the putative catalytic site of human lipoprotein lipase (LPL), mutant LPL cDNAs expressing LPLs with amino acid substitutions of Gly or Asn for Ser¹³² were obtained by site-directed mutagenesis, and were expressed in COS-1 cells. Considerable amounts of LPL enzyme protein mass were detected in the culture medium of COS-1 cells transfected with wild-type LPL, LPL-Gly¹³², or LPL-Asn¹³². LPL-Gly¹³² hydrolyzed Triton X-100-triolein and tributyrin as effectively as wild-type LPL, whereas LPL-Asn¹³² showed no activity. LPL-Asn¹³² bound to very low density lipoproteins as effectively as wild-type LPL.

[学科分类] 生物化学/生物物理

[关键词] Lipoprotein lipase;Catalytic site;Very low density lipoprotein;LPL;lipoprotein lipase;Ser;serine;Gly;glycine;Asn;asparagine;VLDL;very low density lipoproteins;Triton X-100-triolein;triolein emulsified with Triton X-100;Ser132;Ser amino acid residue of 132;LPL-Gly132;LPL with substitution of Gly for Ser132