Some properties of a kidney adenosine triphosphatase relevant to active cation transport

RNA-CONTAINING PARTICLES FROM HEVEA LATEX 495 fraction appears to be strongly associated with the polyisoprenoid particles. 'Bottom fraction' solids contain RNA particles which are mainly associated with readily sedimentable material and which are liberated therefrom by treatment with deoxycholate. The free particles have the characteristics of ribosomal bodies in that they contain 25-30 % of nucleic acid, dissociate into sub-units in the absence of bivalent cations and have the typical negatively-stained fenestrated appearance in phosphotungstic acid. The probable helical substructure of these RNA particles re- ceives confirmation from the observation that on heating their aqueous preparations the extinction maximum in the ultraviolet region increases by an amount which is attributable to a breakdown of a 40 % helical organization of such molecules (Hall & Doty, 1959). This value is similar to that found by these authors and by The presence of 60s and 80s particles has been detected in E. coli by The present results on Hevea are in conformity with such work. SUtMMARY 1. The isolation from Hevea latex of ribosomal particles containing 25 % of RNA and their nucleo- tide analysis is described.