scholarly journals Studies of cytochrome synthesis in rat liver

1973 ◽  
Vol 134 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Robert Druyan ◽  
Smilja Jakovcic ◽  
Murray Rabinowitz
Keyword(s):  
Amino Acid ◽  
Cytochrome C ◽  
Rat Liver ◽  
Cytochrome B5 ◽  
Liver Protein ◽  
Protein Synthesis Inhibitors ◽  
Microsomal Cytochrome ◽  
Microsomal Cytochrome B5 ◽  
Parallel Fashion

The incorporation of radioactive amino acids and of δ-amino[2,3-3H2]laevulinate into rat liver cytochromes b5 and c and cytochrome oxidase has been examined with and without protein-synthesis inhibitors. Cycloheximide promptly inhibits labelling of both haem and protein for cytochrome c in parallel fashion. Although incorporation of 14C-labelled amino acid into microsomal cytochrome b5 is also rapidly inhibited, cycloheximide incompletely inhibits haem labelling of cytochrome b5 and cytochrome a+a3, and inhibition occurs only after repeated antibiotic injections. The possibility of apo-protein pools, or of haem exchange, with a rapidly renewed ‘free’ haem pool, is considered. Consistent with this model is the observation of non-enzymic haem exchange in vitro between cytochrome b5 and methaemoglobin. Chloramphenicol, injected intravenously over 5h, results in a 20–40% decrease in incorporation of δ-amino[2,3-3H2]laevulinate into haem a+a3 and haem of cytochromes b5 and c. With the dosage schedule of chloramphenicol studied, amino acid labelling of total liver protein and of cytochrome c was not inhibited. Similarly, ferrochelatase activity was not decreased.

Insulin stimulus of leucine incorporation into frog liver protein

1962 ◽  
Vol 203 (4) ◽  
pp. 687-689 ◽  
Author(s):  
J. C. Penhos ◽  
M. E. Krahl
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Leucine Incorporation ◽  
Liver Protein ◽  
Amino Acid Incorporation ◽  
Insulin Effect ◽  
Acid Incorporation ◽  
Liver Slices ◽  
Stimulation Of

Slices prepared from livers of bull frogs ( Rana catesbiana), pancreatectomized and/or hypophysectomized 7 days before, were incubated 2 hr in frog Ringer-bicarbonate solution at 25 C. Incorporation of leucine-1-C14 into protein was subnormal in the pancreatectomized series. The addition of insulin in vitro, with glucose also present in the medium, produced a significant ( P < 0.01) stimulation of amino acid incorporation in the following series: livers from normal fed animals; livers from animals pancreatectomized 7 days before; and livers from animals pancreatectomized and hypophysectomized 7 days before. Neither insulin nor glucose alone gave a significant effect. These results therefore confirm and extend those obtained with rat liver slices showing that insulin can stimulate amino acid incorporation into protein when added directly to liver. The effect is relatively greatest with livers from animals pancreatectomized 7 days before; the insulin effect does not depend on the presence of the pituitary, as it is obtainable with livers from animals hypophysectomized and pancreatectomized 7 days previously.

Monoclonal antibodies to rat liver microsomal cytochrome b5

1992 ◽  
Vol 43 (10) ◽  
pp. 2201-2208 ◽  
Author(s):  
Sang S. Park ◽  
Waydell Walker ◽  
Toshifumi Aoyama ◽  
David P. Lapenson ◽  
David J. Waxman ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Rat Liver ◽  
Cytochrome B5 ◽  
Microsomal Cytochrome ◽  
Microsomal Cytochrome B5

Insulin stimulus of leucine incorporation in rat liver protein

1962 ◽  
Vol 202 (2) ◽  
pp. 349-352 ◽  
Author(s):  
J. C. Penhos ◽  
M. E. Krahl
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Leucine Incorporation ◽  
Liver Protein ◽  
Amino Acid Incorporation ◽  
Experimental Conditions ◽  
Maximum Percentage ◽  
Acid Incorporation ◽  
Liver Slices

Slices were prepared from livers of partially pancreatectomized rats and incubated 2 hr in Krebs bicarbonate solution at 37 C. Incorporation of leucine-1-C14 into protein decreased progressively as severity of diabetes increased during 1–6 months after operation; at 2–4 months insulin (0.01 U/ml of medium) plus glucose (200 mg/100 ml) added in vitro stimulated incorporation 62–78%; stimulation was not significant at 6 months. Neither insulin nor glucose was effective separately. Alkali-inactivated insulin was ineffective, even with glucose. Liver slices from sham-operated rats responded similarly to insulin under the present experimental conditions, although the maximum percentage stimulation was smaller than in the partially pancreatectomized series. It is concluded that insulin can act directly on the liver to stimulate amino acid incorporation in protein by a mechanism dependent on the presence of glucose.

scholarly journals The Molecular Weight and Amino Acid Content of Microsomal Cytochrome b5.

1966 ◽  
Vol 20 ◽  
pp. 1999-2001 ◽  
Author(s):  
Rosine Bois-Poltoratsky ◽  
Anders Ehrenberg ◽  
Jorunn Sletten ◽  
Marc Wagnières ◽  
D. H. Williams ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Acid Content ◽  
Cytochrome B5 ◽  
Amino Acid Content ◽  
Microsomal Cytochrome ◽  
Microsomal Cytochrome B5

scholarly journals 1H-n.m.r. investigation of the interaction between cytochrome c and cytochrome b5

1983 ◽  
Vol 215 (1) ◽  
pp. 11-21 ◽  
Author(s):  
C G S Eley ◽  
G R Moore
Keyword(s):  
Cytochrome C ◽  
Association Constant ◽  
Cytochrome B5 ◽  
Bovine Liver ◽  
Candida Krusei ◽  
Microsomal Cytochrome ◽  
Protein Protein Interaction ◽  
Tryptic Fragment ◽  
Microsomal Cytochrome B5 ◽  
Horse Cytochrome

The interaction between eukaryotic cytochrome c and the tryptic fragment of bovine liver microsomal cytochrome b5 was studied by 1H-n.m.r. spectroscopy, and a procedure was developed that may be generally applicable to the study of macromolecular interactions by n.m.r. At pH6.3 (27 degrees C, I approx. 0.04) the two ferricytochromes were found to form a 1:1 complex with an association constant of approx. 10(3) M -1. The protein-protein-interaction region was found to encompass the region of the surface of horse cytochrome c that includes Ile-81, Phe-82, Ala-83 and Ile-85, and Lys-13 and Lys-72 of horse cytochrome c were suggested to be involved in two important intermolecular interactions. Me3Lys-72 of Candida krusei cytochrome c was shown to be involved in the interaction.

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