ISSN:
1432-1424
Keywords:
erythrocyte ghosts
;
liposomes
;
radical interactions
;
protein
;
lipid domains
;
fluidity
;
electron spin resonance
;
spin probes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary A model for the binding of 5-nitroxide stearate, I(12,3). to human erythrocyte ghosts was developed by comparing spin probe interactions with ghosts and liposomes prepared from ghosts. At low probe/lipid (P/L〈1/2500), I(12,3) binds to a similar class of high-affinity, noninteracting sites in both ghosts and liposomes, indicating that lipid moieties are responsible for probe uptake. Saturation occurs in both systems with increasing P/L, and, at higher loading (e.g., P/L=1/360 for ghosts and liposomes), the probe inserts itself at initially dilute sites to form a class of low-affinity sites consisting of clusters of variable size. At still higher P/L ranges (〉1/100), much increased probe uptake was observed in ghosts than in liposomes, which was attributed to another class of low-affinity sites, representing nonspecific interactions of I(12,3) with membrane proteins. The nature of the spectral components and ultrafiltration experiments with ghosts labeled at high P/L indicate that both ‘dilute’ and ‘clustered’ I(12,3) are due to membrane-incorporated probe.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01871779
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