Structure and polymorphism of saturated monoacid 1,2-diacyl-sn-glycerols

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00500a008· OSTI ID:5544691

Kodali, D R; Fahey, D A; Small, D M ^[1]

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1. Boston Univ. School of Medicine, MA (USA)

The 1,2-diacyl-sn-glycerols (1,2-DGs) are the predominant naturally occurring isomer found in cell membranes, lipid droplets, and lipoproteins. They are involved in the metabolism of monoacylglycerols, triacylglycerols, and phospholipids. The authors have undertaken a study of the physical properties of a homologous series of synthetic optically active diacylglycerols. Stereospecific 1,2-diacyl-sn-glycerols were synthesized with saturated fatty acyl chains of 12, 16, 18, 22, and 24 carbons in length. Their polymorphic behavior was examined by differential scanning calorimetry and X-ray powder diffraction. The solvent-crystallized form for all the 1,2-DGs packs in the orthorhombic perpendicular subcell ({beta}{prime}) and melts with a single sharp endotherm to an isotropic liquid. On quenching, the C{sub 12}, C{sub 16} and C{sub 18} compounds pack in a hexagonal subcell ({alpha}), whereas the C{sub 22} and C{sub 24} pack in a pseudohexagonal subcell (sub-{alpha}). The sub-{alpha} phase reversibly converts to the {alpha} phase. The long spacings of these compounds in both the {alpha} and {beta}{prime} phases increase with chain length. In the {alpha} and {beta}{prime} phases, the acyl chain tilts were found to be 90{degree} and 62{degree} from the basal methyl plane. The polymorphic behavior of 1,2-diacyl-sn-glycerol is quite different from that of the corresponding monoacid saturated 1,3-diacylglycerols which form two {beta} phases with triclinic parallel subcells.

• OSTI ID: 5544691
• Journal Information: Biochemistry; (USA), Vol. 29:48; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
GLYCEROL
X-RAY DIFFRACTION
PHOSPHOLIPIDS
METABOLISM
CALORIMETRY
CELL MEMBRANES
ESTERIFICATION
ISOMERIZATION
LIPOPROTEINS
RACEMATES
THERMAL ANALYSIS
ALCOHOLS
CELL CONSTITUENTS
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
ESTERS
HYDROXY COMPOUNDS
LIPIDS
MEMBRANES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PROTEINS
SCATTERING
550602* - Medicine- External Radiation in Diagnostics- (1980-)