E-resources
Peer reviewed
-
Nakanishi, Nobuyuki; Rahman, Md Motiur; Sakamoto, Yoichi; Miura, Masahiro; Takeuchi, Fusako; Park, Sam-Yong; Tsubaki, Motonari
Journal of biochemistry (Tokyo), 12/2009, Volume: 146, Issue: 6Journal Article
Cytochromes b 561 constitute a novel class of proteins in eukaryotic cells with a number of highly relevant common features including six transmembrane α-helices and two haem groups. Of particular interest is the presence of a large number of plant homologues having putative ascorbate- and monodehydroascorbate radical-binding sites. We conducted a diethylpyrocarbonate-modification study employing Zea mays cytochrome b 561 heterologously expressed in Pichia pastoris cells. Pre-treatment of cytochrome b 561 with diethylpyrocarbonate in oxidized form caused N-carbethoxylation of His86, His159 and Lys83, leading to a drastic inhibition of the electron transfer from ascorbate. The activity was protected by the inclusion of ascorbate during the treatment. However, midpoint potentials of two haem centres did show only slight decreases upon the treatment, suggesting that changes in the midpoint potentials were not the major cause of the inhibition. Present results indicated that Zea mays cytochrome b 561 conducted an ascorbate-specific transmembrane electron transfer by utilizing a concerted H+/e− transfer mechanism and that the specific N-carbethoxylation of haem axial His86 that would inhibit the removal of a proton from the bound ascorbate was a major cause of the inhibition. On the other hand, Lys83 might be important for an initial step(s) of the fast electron acceptance from ascorbate.
Shelf entry
Permalink
- URL:
Impact factor
Access to the JCR database is permitted only to users from Slovenia. Your current IP address is not on the list of IP addresses with access permission, and authentication with the relevant AAI accout is required.
Year | Impact factor | Edition | Category | Classification | ||||
---|---|---|---|---|---|---|---|---|
JCR | SNIP | JCR | SNIP | JCR | SNIP | JCR | SNIP |
Select the library membership card:
If the library membership card is not in the list,
add a new one.
DRS, in which the journal is indexed
Database name | Field | Year |
---|
Links to authors' personal bibliographies | Links to information on researchers in the SICRIS system |
---|
Source: Personal bibliographies
and: SICRIS
The material is available in full text. If you wish to order the material anyway, click the Continue button.