Acylglucosylceramides of pig epidermis: structure determination.

The acylglucosylceramides of pig epidermis comprise 56% of the total glucosylceramides and 3.3% of the total epidermal lipid by weight. Contrary to an earlier report on this lipid, the amide-linked fatty acid is not a dihydroxypentatriacontadienoic acid; rather, the fatty acids are a series of long chain omega-hydroxy acids consisting of 58% saturates, 35% monoenes, and 7% dienes, with predominant chain lengths of 30, 32, and 34 carbons, respectively. The structure of the acylglucosylceramides may therefore be formulated as 1-(3'-O-acyl)-beta-D-glucosyl-N-(omega-hydroxy)acylsphingosines. In accord with the previous report, 74% of the total esterified fatty acids is linoleic acid and the long-chain bases consist of homologous series of sphinganines and sphingenines ranging from 16-22 carbons in length. This unique glycolipid may play a role in epidermal barrier function.