Detailed investigations by quantitative centrifugal fractionation were conducted to determine the subcellular distribution of protein-bound sialic acid in rat liver. Homogenates obtained from perfused livers were fractionated by differential centrifugation into nuclear fraction, large granules, microsomes, and final supernate fraction, or were used to isolate membrane preparations enriched in e...

Activities of phosphatidate phosphohydrolase and palmitoyl-CoA hydrolase were determined in cardiac subcellular fractions prepared from rabbits which had received tri-iodothyronine and from hamsters with hereditary cardiomyopathy (strain BIO 14.6). 1. Both mitochondrial and microsomal fractions of hyperthyroid rabbit hearts produced 4-5 times as much diacylglycerol 3-phosphate from glycerol 3-p...

Encephalitogenic basic protein and the enzyme nucleoside 2' :3'-cyclic monophosphate 3'-phosphodiesterase (EC 3.1.4.16) are recognized markers for myelin. Phosphodiesterase activity can be detected in the brains of newborn rats even though myelin cannot be seen by light or electron microscope. The determination of phosphodiesterase activity and the detection of basic protein by Coomassie-Blue s...

acetylneuraminic acid hydrolase the kidney cortex homogenate was subjected to differential centrifugation (see Table 1). Each subcellular fraction obtained was washed twice by repeated centrifugation and the pooled supernatants were then subjected to the next centrifugation step. In this way the homogenate was separated into five particulate fractions and one soluble fraction. The subcellular f...

To understand the mechanism by which human immunodeficiency virus type 1 (HIV) capsids are formed, we have reconstituted the assembly of immature HIV capsids de novo in a cell-free system. Capsid authenticity is established by multiple biochemical and morphologic criteria. Known features of the assembly process are closely reproduced, indicating the fidelity of the cell-free reaction. Assembly ...

The production of prion particles in vitro by amplification with or without exogenous seed typically results in infectivity titers less than those associated with PrP(Sc) isolated ex vivo and highlights the potential role of co-factors that can catalyze disease-specific prion protein misfolding in vivo. We used a cell-free conversion assay previously shown to replicate many aspects of transmiss...