We have used the membrane-impermeable, thiol-cleavable, crosslinker 3,3'-dithio bis (sulfosuccinimidylpropionate) to identify proteins that are in the vicinity of membrane-bound ribosomes of the RER. A specific subset of RER proteins was reproducibly crosslinked to the ribosome. Immunoblot analysis of the crosslinked products with antibodies raised against signal recognition particle receptor, ...

pared with that of normal liver. However, the rate of degradation of membrane protein in the 7800 hepatoma was more rapid than that in its host liver, while the proteins of the reticular membranes of the Morris 9618A hepatoma decayed at a slower rate than did those of its host liver. Despite the varied decay rates, the yields of microsomal membrane protein from the hepatomas were diminished in ...

OBJECTIVES Cytochrome P450 (CYP) 1A1 located in the membrane of endoplasmic reticulum is the most important enzyme in both activation and detoxification of carcinogenic benzo[a]pyrene (BaP), in combination with microsomal epoxide hydrolase (mEH). However, it is still not clearly explained how the electron transfer is mediated by NADPH:CYP oxidoreductase (POR), another component of the microsoma...

We have translated major histocompatibility complex (MHC) class I heavy chains and human beta 2-microglobulin in vitro in the presence of microsomal membranes and a peptide from the nucleoprotein of influenza A. This peptide stimulates assembly of HLA-B27 heavy chain and beta 2-microglobulin about fivefold. By modifying this peptide to contain biotin at its amino terminus, we could precipitate ...

The distribution of nonmitochondrial Ca2+ pumping sites and the site of action of inositol 1,4,5-trisphosphate (Ins 1,4,5-P3) were studied in subcellular fractions of human neutrophils. In homogenates, two different Ca2+ pools could be observed: a mitochondrial Ca2+ pool and a nonmitochondrial, ATP-dependent, Ins 1,4,5-P3-responsive Ca2+ pool. When the homogenate was separated into microsomes, ...

A functional relationship between constitutive enzymes of the endoplasmic reticulum that are involved in lipid metabolism and the proteins and phosphoglycerides constituting those membranes was examined by altering the protein and fat ty acid composition. The specific activity of alkenyl glycerylphosphoryl choline hydrolyase did not change upon fasting, fasting and refeeding or administration o...