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 00:00:00 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), Vol. 30:31; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

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