Electron transfer from cytochrome b5 to iron and copper complexes

Biochemistry ◽  
1987 ◽  
Vol 26 (22) ◽  
pp. 7102-7107 ◽  
Author(s):  
Lorne S. Reid ◽  
Harry B. Gray ◽  
Claudio Dalvit ◽  
Peter E. Wright ◽  
Paul Saltman
Keyword(s):  
Electron Transfer ◽  
Copper Complexes ◽  
Cytochrome B5

Electron-transfer self-exchange kinetics of cytochrome b5

1990 ◽  
Vol 112 (3) ◽  
pp. 1082-1088 ◽  
Author(s):  
Dabney White Dixon ◽  
Xiaole Hong ◽  
Scott E. Woehler ◽  
A. Grant Mauk ◽  
Bhavini P. Sishta
Keyword(s):  
Electron Transfer ◽  
Cytochrome B5 ◽  
Exchange Kinetics ◽  
Kinetics Of

Electron transfer in a P450 BM3/cytochrome b5 complex

1999 ◽  
Vol 27 (3) ◽  
pp. A108-A108
Author(s):  
Michael A. Noble ◽  
W.B. Ost Tobias ◽  
Caroline S. Miles ◽  
Laura Robledo ◽  
Stephen K. Chapman ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cytochrome B5 ◽  
P450 Bm3

ChemInform Abstract: Role of Heme Vinyl Groups in Cytochrome b5 Electron Transfer.

ChemInform ◽  
1987 ◽  
Vol 18 (19) ◽  
Author(s):  
L. S. REID ◽  
A. R. LIM ◽  
A. G. MAUK
Keyword(s):  
Electron Transfer ◽  
Cytochrome B5

scholarly journals Dihydroceramide:sphinganine C-4-hydroxylation requires Des2 hydroxylase and the membrane form of cytochrome b5

2006 ◽  
Vol 397 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Ayako Enomoto ◽  
Fumio Omae ◽  
Masao Miyazaki ◽  
Yasunori Kozutsumi ◽  
Toshitsugu Yubisui ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Erythrocyte Membrane ◽  
Cytochrome B5 ◽  
Soluble Form ◽  
Affinity Column ◽  
Vitro Assay ◽  
Membrane Spanning ◽  
Triton X ◽  
Membrane Spanning Domains

Des2 (degenerative spermatocyte 2) is a bifunctional enzyme that produces phytoceramide and ceramide from dihydroceramide. The molecular mechanism involved in C-4-hydroxylation has not been studied in detail. In the present paper, we report that C-4-hydroxylation requires an electron-transfer system that includes cytochrome b5 and that the hydroxylase activity is reconstituted in an in vitro assay with purified recombinant Des2. FLAG-tagged mouse Des2 was expressed in insect Sf9 cells and was purified by solubilization with digitonin and anti-FLAG antibody affinity column chromatography. The activity of dihydroceramide:sphinganine C-4-hydroxylase was reconstituted with the purified FLAG–Des2, mb5 (the membrane form of cytochrome b5) and bovine erythrocyte membrane. The apparent Km and Vmax of Des2 for the substrate N-octanoylsphinganine were 35 μM and 40 nmol·h−1·mg of protein−1 respectively. The Km of the hydroxylase for mb5 was 0.8 μM. Interestingly, mb5 was not replaced with the soluble form of cytochrome b5, which lacks the C-terminal membrane-spanning domain. The erythrocyte membrane was separated into Triton X-100-soluble and -insoluble fractions, and the detergent-soluble fraction was replaced by the soluble or membrane form of b5R (NADH-cytochrome b5 reductase). The Triton-X-100-insoluble fraction contained trypsin-resistant factors. The Des2 protein is found in the endoplasmic reticulum and is assumed to have three membrane-spanning domains. The findings of the present study indicate that the hydroxylation requires complex formation between Des2 and mb5 via their membrane-spanning domains and electron transfer from NADH to the substrate via the reduction of mb5 by b5R.

Role of heme vinyl groups in cytochrome b5 electron transfer

1986 ◽  
Vol 108 (26) ◽  
pp. 8197-8201 ◽  
Author(s):  
Lorne S. Reid ◽  
Anthony R. Lim ◽  
A. Grant. Mauk
Keyword(s):  
Electron Transfer ◽  
Cytochrome B5
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