Some Observations on the Properdin System : Part VII. Chemical Characterisation of Properdin in relation to its activity Reveals that it contains no Tyrosine in its Polypeptide Moiety

Analysis of different fractions of blood serum exhibiting the biological characteristics of properdin (P) have been carried out with a view to correlating their chemical characteristics and biological activities, The nitrogen, carbon, hydrogen, sulfur and phosphorus contents did not differ much. Although the carbohydrate, hexose, hexosamine and amino-acid nitrogen contents were also nearly equal in different samples, an attempt has been made to correlate the small differences observed in proportions of these components with the activities of the samples. Chromatographic studies of the carbohydrates, lipids and amino-acids of the different samples have been reported. The analysis of the different constituents suggest at present that properdin may be characterised as a lipid-containing glycoprotein of blood serum, whose polypeptide moiety is unique in having no tyrosine in it.