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A Bergstrand

Publications and source records attributed to A Bergstrand.

63 records · Page 4Linked to original sources
PubMed1967

An electron-transport system associated with the outer membrane of liver mitochondria. A biochemical and morphological study.

Preparations of rat-liver mitochondria catalyze the oxidation of exogenous NADH by added cytochrome c or ferricyanide by a reaction that is insensitive to the respiratory chain inhibitors, antimycin A, amytal, and rotenone, and is not coupled to phosphorylation. Experiments with tritiated NADH are described which demonstrate that this "external" pathway of NADH oxidation resembles stereochemically the NADH-cytochrome c reductase system of liver microsomes, and differs from the respiratory chain-linked NADH dehydrogenase. Enzyme distributation data are presented which substantiate the conclusion that microsomal contamination cannot account for the rotenone-insensitive NADH-cytochrome c reductase activity observed with the mitochondria. A procedure is developed, based on swelling and shrinking of the mitochondria followed by sonication and density gradient centrifugation, which permits the separation of two particulate subfractions, one containing the bulk of the respiratory chain components, and the other the bulk of the rotenone-insensitive NADH-cytochrome c reductase system. Morphological evidence supports the conclusion that the former subfraction consists of mitochondria devoid of outer membrane, and that the latter represents derivatives of the outer membrane. The data indicate that the electron-transport system associated with the mitochondrial outer membrane involves catalytic components similar to, or identical with, the microsomal NADH-cytochrome b(5) reductase and cytochrome b(5).

Animals↗
PubMedDate not supplied

Release of rat liver endoplasmic reticulum membrane proteins into the cytosol.

A membrane-free supernatant is prepared from rat liver cell homogenate by centrifugation at 230,000 x g. AMPase, NADH- and NADPH-cytochrome c reductase activities are demonstrated in the supernatant. These enzymes can be released from rough microsomal membranes by incubation in 0.25 M sucrose at 37 degrees C for 30 minutes. This release is time and temperature dependent and decreases in presence of phospholipase inhibitors. These results indicate that transfer of membrane enzymes from membranes to the cytosol may take place also in vivo. The process seems to be due to an enzymatic digestion of membranes and may be a mechanism for membrane turnover in addition to autophagocytosis.

Adenosine Monophosphate↗