Heparin in molluscs: chemical, enzymatic degradation and 13C and 1H n.m.r. spectroscopical evidence for the maintenance of the structure through evolution.

The structural features and anticoagulant activity of heparins isolated from three species of molluscs (Anomalocardia brasiliana, Donnax striatus and Tivela mactroides) are reported. It is shown by chemical analyse, type of products formed by action of heparinase and heparitinase II, anticoagulant activity, 13C and 1H n.m.r. spectroscopy, that the mollusc heparins are virtually indistinguishable from heparins present in mammalian tissues. These data, taken as a whole, suggest that heparin has maintained its main structural features through evolution. The implications of these findings are discussed.