The proteins of Hevea brasiliensis latex. 1. Protein constituents of fresh latex serum

Abstract

The aqueous serum phase of unpreserved rubber latex (Hevea brasiliensis) has been separated in 2 ways: (a) by high-speed centrifuging, and (b) by prolonged freezing at -25[degree]. The protein contents of the serum solids are approximately 18 and 13%, respectively; the difference is attributed to coagulation of protein during prolonged freezing of the latex. There is evidence that organic phosphorus compounds (probably phospholipids) are partially hydrolysed during the freezing process, and that enzymic or bacterial reactions occur, leading to a fall in pH of the serum. In both types of serum, 7 electrophoretically distinct protein components have been detected, one of which is positively charged at pH 8.6. After treatment with dilute ammonia solution for 15 days, only 2 of the original protein components are readily resolvable electrophoretically''. One of these (no. 5) is a major component of the unammoniated serum.