The C-3 hydroxyl group is esterified to phosphoric acid. Linolein is a triglyceride in which glycerol is esterified with linoleic acid. In sphingomyelin the primary hydroxyl group of sphingosine is esterified to phosphoryl choline. In nature, around 80 percent of carboxyl groups of galacturonic acid are esterified with methanol. Palm oil, like all fats, is composed of fatty acids, esterified with glycerol. Isopropyl alcohol is esterified to give isopropyl acetate, another solvent. The unprotected diol can then be esterified further to form either the di- or triglyceride. Most ingested cholesterol is esterified, which causes it to be poorly absorbed by the gut. In another method BINOL is esterified with pentanoyl chloride. It contains esterified ampicillin and sulbactam. Esterified ALA derivatives with improved bioavailability have been examined.