Interaction of cholesterol with sphingomyelin in bilayer membranes: Evidence that the hydroxy group of sphingomyelin does not modulate the rate of cholesterol exchange between vesicles

Journal Article · Tue Aug 06 04:00:00 EDT 1991 · Biochemistry; (United States)

OSTI ID:5822334

Kan, Chucheng; Ruan, Zhongshi; Bittman, R ^[1]

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1. City Univ. of New York, Flushing (United States)

Cholesterol undergoes exchange between membranes containing sphingomyelin at a much slower rate than between membranes lacking sphingomyelin. To investigate the role of the hydroxy group at the 3-position of sphingomyelin in the interaction between sphingomyelin and cholesterol, the authors have measured the rates of (4-{sup 14}C)cholesterol exchange between unilamellar vesicles prepared with N-alkyl group or with hydrogen. Vesicles prepared from 3-deoxy- and 3-0-methyl-N-stearoylsphingomyelin had the same rate of ({sup 14}C) cholesterol desorption. The half-times for exchange from vesicles prepared with 3-0-methyl- and 3-deoxy-N-stearoylsphingomyelins and 10 mol% of cholesterol were only slightly faster than that found from vesicles prepared from N-stearoylsphingomyelin and 10 mol% cholesterol. The rate of cholesterol desorption from vesicles could be accelerated by preparing vesicles from bulky 3-0-alkyl analogues of sphingomyelin. These data indicate that insertion of sterically bulky groups at the 3-position of sphingomyelin in place of hydroxy interferes markedly with the molecular packing of cholesterol and sphingomyelin in bilayer membranes; however, the hydroxy group of sphingomyelin is not critical for the strong interaction of cholesterol with sphingomyelin. These results suggest that van der Waals interactions are more important than hydrogen-bonding interactions involving the hydroxy group in contributing to tight lateral packing of cholesterol with sphingomyelin.

• OSTI ID: 5822334
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:31; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMICAL REACTION KINETICS
CALORIMETRY
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
CHOLESTEROL
CROSS-LINKING
ESTERS
HYDROXY COMPOUNDS
KINETICS
LABELLED COMPOUNDS
LIPIDS
MEMBRANES
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXIDATION
PHOSPHOLIPIDS
POLYMERIZATION
REACTION KINETICS
SPHINGOMYELINS
STEROIDS
STEROLS