Abstract
The histochemical use of methylation has complex results; particularly in respect of the periodic acid-Schiff reaction, these are analyzed and discussed. Methods are described which allow the separate study of the following effects: (a) the removal of the KOH/periodic acid-Schiff effect; (b) removal of sialic acid from a potential vicinal diol; and (c) the removal of O-sulfate ester from a potential vicinal diol. The use of the Smith degradation technique, in addition to the above, also allows inferences to be drawn in respect of the structure of the mucins (glycoproteins) being investigated.