The relationship of carbohydrates and peptides in human fibrinogen and fibrin

Abstract

Three purified human plasma proteins, albumin, CK1-glycoprotein (prepared according to Schmid) and 96 per cent clottable fibrinogen (prepared according to Blomback, fraction I4) were found to react with 1 M hydrazine at pH 9.0 under conditions similar to those used by Gallop, et al. for determining the ester-like bonds in collagen. The moles of "heat-labile" hydrazine per mole of each human plasma protein studied were approximately: 0.2 for albumin, 0.3 for alpha1-glycoprotein, and 3.4 for fibrinogen. The spectral absorption curves of the "heat-labile" hydrazine derived from the treated proteins were comparable with those obtained for the hydrazine standards. The kinetics of reaction time and the pH optimum for the formation of fibrinogen-hydrazide were studied. The small amounts of hydrazine reacted with alpha1-glycoprotein would suggest that the hydroxyl groups of the carbohydrate moiety of glycoproteins are not involved in the hydrazine reaction used in these experiments. The amounts of hydrazine reacted with albumin would suggest that the hydrazine reaction with the plasma proteins used in this investigation is unique for fibrinogen. [TRUNCATED]