EFFECTS OF SPERMINE ON THE RIBONUCLEOPROTEIN PARTICLES 24I 



Spermine was used in each experiment, and from 250 c.p.m. to 1000 c.p.m. 

 were recovered in the particles in the various experiments; this is much 

 more than would be expected from contamination, since the particles 

 were well washed after centrifugation. In the experiments in which the 

 release of radioactive spermine from the particles was followed, the 

 following conditions were used: The particles were incubated with radio- 

 active spermine as given above. They were then centrifuged, washed 

 extensively, and resuspended by homogenization in cold distilled water. 

 An aliquot of this suspension was then removed for immediate chemical 

 and radioactive analyses, while another aliquot was incubated at 35° for 

 30 min. with various additions in a total volume of i -o ml. After incuba- 

 tion, water was added, the suspension centrifuged at 105 000 x g for 90 

 min., and the pellet was resuspended in water and assayed as above. All 

 the compounds used in the experiments were brought to pH 7-0. The 

 radioactive spermine, specific activity approximately o • i jU,c//xmole, was 

 labelled with "C in the i and 4 positions of the butane part of the mole- 

 cule ([i,4-i^C]-i,4-di-(i',3'-diamino propyl) butane) and was obtained 

 through the generosity of Drs. H. Waelsch and D. Clarke. 



Results 



In a previous paper [7], it was reported that P-P, or even ATP or GTP, 

 at a cone, of 5 x 10^* m, could release from 80 to 100° of the bound 

 amylase, RNase, and TAPase activities of the RNP particles, after incuba- 

 tion of the particles at 35° for 30 min. Table I shows, again as a com- 

 parison, the results of further experiments with P-P and also the results 

 of experiments with various amines and other compounds. Spermine, 

 even at 5 x lo"^ M, could release the amylase activity from the particles. 

 In experiments not shown, spermine at io~* M was equivalent to P-P at 

 5 X ID"'* M in releasing also the RNase and TAPase activities of the 

 particles. Putrescine and cadaverine, while effective, could not release the 

 amylase activity as well as spermine, and it would seem that the ability to 

 release the enzymic activity is related to the number of amine groups and 

 hence the charge on the molecule. As can be seen, histamine, lysine, and 

 ornithine had some effect, while even tris buffer had an effect, but a 

 marked one only at 5 x lO"^ M. It is noteworthy that pilocarpine, car- 

 bamylcholine, and acetylcholine have very little, if any, effect on the 

 amylase release, as compared to incubation in water. 



The P-P release of the bound enzymic activities of the particles is 

 probably a consequence of the concomitant release of all the Mg + + and 

 most of the RNA of the particles [7]. Table II shows, again further 

 experiments with P-P, and with various amine compounds, on the dis- 

 charge of Mg + + and of RNA from the particles. However, unlike P-P, 



