Ferritin Synthesis by Free and Membrane-Bound (Poly)ribosomes of Rat Liver

1971 ◽  
Vol 138 (2) ◽  
pp. 399-403 ◽  
Author(s):  
D. G. Puro ◽  
G. W. Richter
1974 ◽  
Vol 138 (2) ◽  
pp. 305-307 ◽  
Author(s):  
K. O'Toole

A rough-membrane fraction isolated from rat liver by a procedure designed to prevent membrane denaturation was subjected to the gradient treatment normally used to isolate free ribosomes. Under these conditions, at most 20% of the ribosomes were detached from membrane with less than 5% sedimenting into the free-polyribosome pellet.


1977 ◽  
Vol 168 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J C Ramsey ◽  
W J Steele

Free loosely bound and tightly bound polyribosomes were separated from rat liver homogenate by salt extraction followed by differential centrifugation, and several of their structural and functional properties were compared to resolve the existence of loosely bound polyribosomes and verify the specificity of the separation. The free and loosely bound polyribosomes have similar sedimentation profiles and polyribosome contents, their subunit proteins have similar electrophoretic patterns and their products of protein synthesis in vitro show a close correspondence in size and amounts synthesized. In contrast, the tightly bound polyribosomes have different properties from those of the free and loosely bound polyribosomes; their average size is significantly smaller; their polyribosome content is higher; their 60 S-subunit proteins lack two components and contain four or more components not found elsewhere; their products of protein synthesis in vitro differ in size and amounts synthesized. These observations show that rat liver membranes entrap a large fraction of the free polyribosomes at low salt concentrations and that these polyribosomes are similar to those of the free-polyribosome fraction and are different from those of the tightly bound polyribosome fraction in size, structure and function.


1991 ◽  
Vol 12 (2) ◽  
pp. 113-120 ◽  
Author(s):  
MITSUAKI YANAGIDA ◽  
YOSHIAKI TAMANOUE ◽  
KAZUO SUTOH ◽  
TAKAYUKI TAKAHASHI ◽  
KENJI TAKAHASHI

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