Thromb Haemost 1986; 55(02): 162-167
DOI: 10.1055/s-0038-1661514
Original Article
Schattauer GmbH Stuttgart

Localization of a Thrombin-Binding Site on Human Platelet Membrane Glycoprotein Ib Determined by a Monoclonal Antibody

K Yamamoto
The Department of Cardiovascular Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
,
N Yamamoto
The Department of Cardiovascular Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
,
H Kitagawa
The Department of Cardiovascular Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
,
K Tanoue
The Department of Cardiovascular Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
,
G Kosaki
1   The Tokyo Metropolitan Komagome Hospital, Tokyo, Japan
,
H Yamazki
The Department of Cardiovascular Research, The Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
› Author Affiliations
Further Information

Publication History

Received 27 September 1985

Accepted 13 December 1985

Publication Date:
18 July 2018 (online)

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Summary

To determine a thrombin-binding site on GPIbα on platelet membrane, we have examined the binding activities of tryptic or chymotryptic fragments of purified GPIbα to a monoclonal antibody against GPIb (TM60) and thrombin using (immuno) affinity chromatography. When purified GPIba was digested with trypsin, two fragments (94-kDa, and 43-kDa) were obtained. The 43-kDa fragment was shown to bind to both affinity columns of TM60- and thrombin-Affi-Gel, while the 94-kDa fragment did not bind to either Affi-Gel columns. When trypsin fragments were incubated with TM60 and then applied to the column of thrombin-Affi-Gel, neither fragments were bound to the column. When the same experiment was performed using chymotrypsin, three fragments (94-kDa, 45-kDa and 39-kDa) were observed. On TM60- and thrombin-Affi-Gel columns, the smaller fragments (45-kDa and 39-kDa) were bound to the column. After incubation of these fragments with TM60, neither bound to the thrombin column. These results indicate (i) that the epitope for TM60 is located near, or on the thrombin-binding site of GPIba, and (ii) that the thrombin-binding site is located on the tail portion of GPIbα, especially on a chymotrypsin cleavage site.