65] Sialic acids and derivatives: Preparation

Abstract

Publisher Summary This chapter describes the preparation of sialic acids and derivatives. The term sialic acids are a group name for acylated nonulosaminic acids, which exist in nature. N -Acetylneuraminic acid is the most commonly occurring acid and exists alone in all the tissues of man, birds, reptiles, and fishes. In all other mammals investigated, N -acetyl- and N -glycolylneuraminic acids occur together in the tissues, except in the central nervous system, where there is N -acctylneuraminic acid only. N -Acetylneuraminic acid free from N -glycolylneuraminic acid is suitably prepared from human material. The acid is liberated by mild acid hydrolysis from its natural source and purified by ion-exchange chromatography. Bovine submaxillary mucin is isolated and purified by isoelectric precipitation. The sialic acids are liberated by boiling water and separated by cellulose column chromatography. The fractions containing the di- and triacetylneuraminic acids are pooled separately and evaporated below 0° to dryness. All sialic acids, but not methoxyneuraminic acid, reduce Fehling's solution. It is found that N -Acetylneuraminic and N -glycolylneuraminic acids consume 2 moles of periodate and form 1 mole of formic acid and about 1 mole of formaldehyde.