A plasma membrane fraction prepared from human neutrophils had a fluorescence resembling that of a fluorescent flavoprotein, with emission maximum near 520nm and excitation maxima near 380 and 460nm. The fluorescence emission and excitation properties of Triton N-101-solubilized membrane fraction resembled those of FAD. FAD was present in the membranes at a concentration of 417pmol/mg of protein and cytochrome b–245 at a concentration of 407pmol/mg of protein. In a 110-fold purified preparation of cytochrome b–245 the ratio of FAD:cytochrome b was 1:1. Analytical gradient centrifugation of neutrophil homogenates shows a coincidence of two cytochrome b peaks and two peaks of fluorescence, corresponding with plasma membrane and specific granule fractions; most of the FAD was non-fluorescent and located in fractions lighter than the plasma membrane. Plasma membrane fractions prepared from neutrophils of patients suffering from the X-linked form of chronic granulomatous disease lacked cytochrome b and contained 194pmol of FAD/mg of protein; plasma membrane fractions prepared from neutrophils of patients with the autosomal recessive form of chronic granulomatous disease contained both cytochrome b–245 and FAD in the normal range of concentrations in a ratio of 1:1. Phagocytic vesicles were prepared from normal neutrophils and found to contain FAD and cytochrome b in a ratio 2.22:1, suggesting that activation of neutrophils many involve the incorporation of an additional flavin into the membrane. Under anaerobic conditions in the presence of EDTA to act as an electron donor to a flavin, the cytochrome b–245 of neutrophil membranes was partly (12%) photoreducible, an effect increased to 100% by the addition of FMN. The extent of reduction of cytochrome b in an anaerobic neutrophil homogenate containing NADH increased from 30% to 70% on illumination. We suggest that these results indicate a close association between FAD and cytochrome b–245 and support a scheme for electron transport thus: [Formula: see text]
Skip Nav Destination
Article navigation
December 1982
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
December 15 1982
The association of FAD with the cytochrome b–245 of human neutrophils
Andrew R. Cross;
Andrew R. Cross
1Department of Biochemistry, The Medical School, University of Bristol, Bristol BS8 1TD, U.K.
Search for other works by this author on:
Owen T. G. Jones;
Owen T. G. Jones
2Department of Biochemistry, The Medical School, University of Bristol, Bristol BS8 1TD, U.K.
Search for other works by this author on:
Rudolfo Garcia;
Rudolfo Garcia
3Department of Haematology, School of Medicine, University College, London W.C.1., U.K.
Search for other works by this author on:
Anthony W. Segal
Anthony W. Segal
4Department of Haematology, School of Medicine, University College, London W.C.1., U.K.
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1982 London: The Biochemical Society
1982
Biochem J (1982) 208 (3): 759–763.
Citation
Andrew R. Cross, Owen T. G. Jones, Rudolfo Garcia, Anthony W. Segal; The association of FAD with the cytochrome b–245 of human neutrophils. Biochem J 15 December 1982; 208 (3): 759–763. doi: https://doi.org/10.1042/bj2080759
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.