Mannosidases in Glycoprotein Processing and Catabolism

Although a-D-mannosidase appears to be under endocrine control,28,28 its natural function remains obscure. It is probable that the enzyme is important in the catabolism of D-mannose-containing glycoproteins,12,16,88 and, therefore, that the important trace element zinc could be indirectly implicated in this process. It is well known that zinc deficiency has an adverse effect on fertility in the male,89,90 and it could be argued that the changes observed in a-D-mannosidase activity in uterus and epididymis indicate that this enzyme is important in reproduction. It is scarcely justifiable to ascribe a cause-and-effect relationship to the correlations observed between the zinc content and the a-D-mannosidase activity in epididymis. All that can be said with any certainty is that, under certain circumstances, the two variables respond together to a common stimulus. 

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