ON BLOOD FIBRIN

Abstract

Recently a reagent for the quantitative isolation of proline was developed in this laboratory, and with its aid it was shown that in gelatin the amino acids, glycine, proline, and hydroxyproline, occurred in molar quantities defined by the simple numerical ratio of 6:3 : 2 (1).These results are reproduced in Table I, supplemented by analytical values for arginine, lysine, leucine-isoleucine, and alanine.In view of the striking regularities noted in the case of gelatin, it became desirable to determine the validity of similar relationships in a second protein.Blood fibrin was chosen as a typical example and two commercial preparations were obtained for analysis.One was of foreign origin (Hoffmann-La Roche, Basel) and the other domestic (Eimer and Amend, New York).Only those amino acids were determined for which trustworthy quantitative methods were available.The percentage composition thus obtained is presented in Table II, and the values are compared with those resulting from previous investigations.It is of interest to note that the yields obtained in this study for proline, glutamic acid, and aspartic acid are significantly higher than those reported earlier.The percentage composition recorded in Column 1 of Table II was recalculated on a gm.molecular basis, and is presented in this form in Table III.On examination of Column 3 of Table III, it is seen that beef fibrin produces equivalent amounts of arginine, aspartic acid, and prolme on hydrolysis.This fact suggests that the formation of beef fibrin from its constituent parts follows, in one way or another, certain stoichiometrical principles.