The preparation and properties of thrombin, together with observations on antithrombin and prothrombin / by W.H. Howell.

  • William Henry Howell
Date:
[1910?]
Catalogue details

Licence: Public Domain Mark

Credit: The preparation and properties of thrombin, together with observations on antithrombin and prothrombin / by W.H. Howell. Source: Wellcome Collection.

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    washed fibrin with strong saline is used, the solution contains much protein. When fresh fibrin from the dog is used, and, after thorough washing in water, is digested for twenty-four hours with 8 per cent solution of sodium chloride at 40° C., it is nearly all dissolved, and the filtered solution gives a very abundant precipitate on heating to 57° to 60° C., and usually a second much smaller precipitate when heated further to 76°-80° C. The presence of these large amounts of pro- tein in solution makes it difficult or impossible to study satis- factorily the properties of the thrombin itself. An effort was made accordingly to remove the protein without precipitating the thrombin. A method was finally devised which effected this result, as follows: METHOD OF PREPARING PURE THROMBIN. A large quantity of fibrin obtained by whipping pig’s blood is thor- oughly washed in running water until it is entirely freed from hemo- globin. The process is tedious, taking several hours, as the fibrin must be continually kneaded in the running water, and the larger masses must be shredded by hand to remove the enclosed hemoglobin. The white mass finally obtained is minced finely and thoroughly squeezed in cheese cloth, and is then placed in a vessel and covered with an 8 per cent solution of sodium chloride. This preparation is kept in the ice chest for forty-eight to seventy-two hours and is then filtered, first through cheese cloth and then through filter paper. The somewhat viscid solution thus obtained has a powerful thrombin action. To remove the coagulable protein contained in it it was shaken repeatedly with chloroform, adding each time about one half its vol- ume of chloroform, shaking vigorously in the hand or a shaking ma- chine and then filtering through filter paper. At first a heavy precipi- tate is produced and the liquid above the chloroform is turbid and gives a turbid filtrate. But as the process is repeated again and again, the filtrate becomes clearer and comes through more rapidly. Each time that this filtrate is shaken with new chloroform, the latter quickly forms an emulsion which on standing sinks to the bottom. When the filtrate is entirely clear, or shows only a slight opalescence when seen in bulk, it continues to form an emulsion when shaken with the chloro- form, and the process must be continued until after prolonged shaking with fresh chloroform the latter on standing forms a clear layer without
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