[Isolation of platelet integrin GPIIbIIIa, preparation of its chymotrypsin fragments and IIIa subunit].

The method for isolation of glycoprotein IIbIIIa by chromatography on Concanavalin A-Sepharose and DEAE-Sephacel columns have been proposed. The 66 kDa, 27 kDa and 6 kDa fragments were produced by chymotrypsin digestion of GpIIbIIIa and purified with FPLC system on Superose-12 column under non denaturating conditions. N-terminal sequence analysis of fragments revealed that 66 kDa fragment contained NH2-terminal region, disulphide rich node, transmembrane and cytoplasmatic regions of IIIa subunit. 27 kDa fragment was a part of Ca(2+)-binding site of IIb subunit. 6 kDa fragment was shown to be from transmembrane and cytoplasmatic regions of IIb subunit. GpIIIa was isolated by gel-filtration on Sephacryl S-300 column of the GpIIbIIIa dissociated.