Identity of urinary trypsin inhibitor-binding protein to link protein.
Urinary trypsin inhibitor (UTI), a Kunitz-type protease inhibitor, directly binds to some types of cells via cell-associated UTI-binding proteins (UTI-BPs). Here we report that the 40-kDa protein (UTI-BP(40)) was purified from the cultured human chondrosarcoma cell line HCS-2/8 by UTI affinity chromatography. Purified UTI-BP(40) was digested with trypsin, and the amino acid sequences of the peptide fragments were determined. The sequences of six tryptic fragments of UTI-BP(40) were identical to subsequences present in human link protein (LP). Authentic bovine LP and UTI-BP(40) displayed identical electrophoretic and chromatographic behavior. The UTI-binding properties of UTI-BP(40) and LP were indistinguishable. Direct binding and competition studies strongly demonstrated that the NH(2)-terminal fragment is the UTI-binding part of the LP molecule, that the COOH-terminal UTI fragment (HI-8) failed to bind the NH(2)-terminal subdomain of the LP molecule, and that LP and UTI-BP(40) exhibited significant hyaluronic acid binding. These results demonstrate that UTI-BP(40) is identical to LP and that the NH(2)-terminal domain of UTI is involved in the interaction with the NH(2)-terminal fragment of LP, which is bound to hyaluronic acid in the extracellular matrix.
Kobayashi
H
H
Department of Obstetrics and Gynecology and the Equipment Center, Hamamatsu University School of Medicine, Handacho 3600, Hamamatsu, Shizuoka 431-3192.
Hirashima
Y
Y
Sun
G W
GW
Fujie
M
M
Nishida
T
T
Takigawa
M
M
Terao
T
T
D053674:Aggrecans; D000595:Amino Acid Sequence; D000818:Animals; D001859:Bone Neoplasms; D002417:Cattle; D002813:Chondrosarcoma; D002846:Chromatography, Affinity; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D006820:Hyaluronic Acid / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D037181:Lectins, C-Type; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism; D014357:Trypsin; D014361:Trypsin Inhibitors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000099249:Proteoglycan Link Protein
D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid; D037181:Lectins, C-Type; D010446:Peptide Fragments; D011506:Proteins; D011509:Proteoglycans; D014357:Trypsin; D014361:Trypsin Inhibitors; D000099249:Proteoglycan Link Protein; C028665:urinastatin