Purification and characterization of a novel glycoprotein which has significant homology to heavy chains of inter-alpha-trypsin inhibitor family from human plasma.
Plasmapheresis with a dextran sulfate column is a treatment for patients with hypercholesteremia. When proteins bound to the column during the treatment were fractionated to prepare some known proteins, we found a 57 kDa glycoprotein designated GP57 which showed a new N-terminal amino acid sequence. Western-blot analysis of human plasma revealed that only a 120 kDa protein, GP120, reacted with anti-GP57 antibody. Since GP120 and GP57 had an identical N-terminal amino acid sequence, GP120 is probably the intact form of GP57. The isoelectric point of GP120 was 6.8. N-Glycanase treatment decreased the molecular weight of GP120 by 15 kDa. Neuraminidase and O-glycanase, however, did not affect the molecular weight. Amino acid sequence analyses of the lysylendopeptidase digest of GP120 revealed significant homology to the heavy chains of inter-alpha-trypsin inhibitor (ITI) family. Since GP120 showed no bikunin sequence, and chondroitinase treatment and alkaline treatment of GP120 did not affect its molecular weight, we concluded that GP120 was not a complex with bikunin. We designated GP120 as IHRP (ITI heavy chain-related protein).
Choi-Miura
N H
NH
Department of Physiological Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo.
Sano
Y
Y
Oda
E
E
Nakano
Y
Y
Tobe
T
T
Yanagishita
T
T
Taniyama
M
M
Katagiri
T
T
Tomita
M
M
D000510:Alpha-Globulins / Q000737:chemistry*; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D016264:Dextran Sulfate; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000097:blood* / Q000737:chemistry* / Q000302:isolation & purification; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood* / Q000302:isolation & purification; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D005810:Multigene Family; D010956:Plasmapheresis; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases
D000510:Alpha-Globulins; D006023:Glycoproteins; D008077:Lipoproteins, LDL; D046911:Macromolecular Substances; C011877:inter-alpha-inhibitor; D016264:Dextran Sulfate; D012697:Serine Endopeptidases; C036813:lysyl endopeptidase