2010م - 1444هـ
نبذه عن الكتاب:



Expression and Purification of the Amphipathic

Form of Rabbit Cytochrome b5 in Escherichia coli

Lucy Waskell

1. Introduction

Cytochrome b5 (cyt b5

) is an electron transfer protein that exists in a

membrane-bound form in the endoplasmic reticulum where it is anchored to the

membrane via a carboxyl-terminal transmembrane
-helix (1–3). The

membrane-bound form of cyt b5 provides reducing equivalents for the biosynthesis of a variety of lipids including unsaturated fatty acids, plasmalogens, and

cholesterol. In addition, it facilitates the cytochrome P450 catalyzed oxidation

of selected substrates (2). The membrane domain is linked to the aminoterminal catalytic heme-containing domain via an 11 amino acid linker. The

mammalian cyts b5 are typically greater than 90% similar in sequence and may

be interchangeable in some systems (4). Nevertheless, our laboratory uses rabbit cytochrome P450 2B4 and cytochrome P450 reductase and has elected to

use the rabbit cyt b5 so all proteins are from a single species. Cyt b5 also exists

in a soluble form in red blood cells where it functions to maintain hemoglobin

in its ferrous oxygen-carrying form (5).