DIFFERENCES IN PEPTIDE MAPS OF a POLYMERS FROM FIBRIN PRODUCED IN THE PRESENCE AND ABSENCE OF ERYTHROCYTES

α chain polymerisation during clot formation is accelerated in the presence of erythrocytes. This effect is abrogated if the erythrocytes are obtained from patients with various haemoglo-binopathies. Enzyme digests of the α polymers produced in the presence or absence of erythrocytes were prepared to further define any differences between them.Clots were produced from citrate/EACA plasma samples or plasma/erythrocyte mixtures by the addition of thrombin and calcium. After five hours, clots were washed iii 8 M urea until traces of haemoglobin were removed. After reduction and alkylation clots were dissolved in 0.5% SDS. a polymers were purified on sephacryl S-300 and protein concentrations were adjusted to 0.5 mg/ml. These were digested with S. Aureus V8 protease (150 mg/ml), papain (50 mg/ml) or chymotrypsin (100 mg/ml) at 37°C at sequential time intervals.After the addition of 2% SDS samples were analysed on 15% SDS polyacrylamide gels.In all cases digestion of a polymers from clots formed in the absence of erythrocytes took place more rapidly and contained peptide bands not apparent in other digests.The observations suggest that α polymers formed in the presence or absence of erythrocytes exhibit differing kinetics of response to proteolytic cleavage and indicate that erythrocytes may influence the primary and/or quartenary structure of the polymers studied.