Galactomuramic Acid: CHEMICAL SYNTHESIS, PROPERTIES, ASSAY, AND SURVEY IN SEVERAL BACTERIAL SPECIES

Abstract

Abstract Synthetic d-galacto- and d-glucomuramic acids were prepared from the condensation of l-α-chloropropionic acid with benzyl-2-acetamido-4,6-O-benzylidene-2-deoxy-α-d-galacto- or glucopyranoside. The configuration of the d(-) lactate moiety (i.e. 3-O-(d-1-carboxyethyl)-) obtained by alkaline β elimination, was proven by use of specific d(-)- and l(+)-lactic acid dehydrogenases. Standard methods commonly used for the detection of muramic acid were found to be unsuitable for distinction between the two products. Thus, although the Barker and Summerson, Morgan-Elson, Park-Johnson, and Rondle-Morgan tests were shown to detect both gluco and galacto epimers of muramic acid (color yields differed slightly), such colorimetric assays could not differentiate between the analogues. Ionophoresis did not distinguish the forms of muramic acid, and thin layer chromatography was found to be suitable for distinction only under carefully controlled conditions. Cation exchange chromatography, according to Gardell, was used successfully in the separation of the glucomuramic and galactomuramic acids, but it was found that glucosamine co-elutes with galactomuramic acid. The most rapid and precise detection method was that in which a commercial amino acid analyzer was used. Detection of nanomole quantities of material was possible. The muramic acid content of 16 bacterial species was determined. Only the glucomuramic acid analogue was found.