Factor H co-purifies with thrombospondin isolated from platelet secretate

被引:14
作者
Carron, JA
Bates, RC
Smith, AI
Tetoz, T
Arellano, A
Gordon, DL
Burns, GF
机构
[1] UNIV NEWCASTLE, FAC MED, CANC RES UNIT, ROYAL NEWCASTLE HOSP, NEWCASTLE, NSW 2300, AUSTRALIA
[2] BAKER MED RES INST, PEPTIDE BIOL LAB, PRAHRAN, VIC 3181, AUSTRALIA
[3] FLINDERS MED CTR, DEPT MICROBIOL & INFECT DIS, BEDFORD PK, SA, AUSTRALIA
来源
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS | 1996年 / 1289卷 / 03期
基金
英国医学研究理事会;
关键词
factor H; thrombospondin; heparin affinity; contamination; glycoprotein;
D O I
10.1016/0304-4165(95)00095-X
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Thrombospondin is a trimeric glycoprotein that has several known functions, including roles in platelet aggregation, phagocytosis and an inhibitor of angiogenesis. Typically the molecule is isolated from platelet secretate by heparin affinity followed by sizing chromatography. In this study, purity is analysed by 7.5% SDS-PAGE under reducing conditions when thrombospondin monomers run as a band at around 180 kDa. Under nonreducing conditions of 7.5% SDS-PAGE, thrombospondin does not penetrate beyond the stacking gel; however, under these conditions a major contaminating band can be seen which, upon reduction, merges into the thrombospondin band. Further purification of this contaminating protein was achieved by DEAE chromatography and it was identified as Factor H by peptide sequencing and immunoblotting. Factor H function was demonstrated by the ability of the protein to function as a cofactor in the Factor-I-mediated cleavage of C3b. Since Factor H has several known functions, such contamination could confound functional studies of thrombospondin thus purified and a pre-elution step of the heparin affinity column is recommended.
引用
收藏
页码:305 / 311
页数:7
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