Manganese is absorbed with about 4% efficiency from the
intestines and is carried into, and in the blood by the protein transmanganin.
Regulation of body manganese levels is controlled primarily through variable
excretion, rather than absorption.
Manganese is essential for the enzymatic incorporation of
xylose and galactose in glycoproteins. These glycoproteins are the cells
natural barrier to invading viruses and coat every cell of the human body.
Glycoproteins also make up the great majority of all secretory proteins.
Manganese and magnesium are used interchangeably in many
enzymes as cofactors. Aminopeptidases, which break down protein structure, are
secreted by the intestinal mucosal cells for digestive purposes and utilize
either magnesium or manganese as the cofactor element of their structures.
Manganese is an important constituent of activated
arginase, an enzyme found in the liver, and mediates the conversion of arginine
Manganese is a constituent of the enzyme, pyruvate
carboxylase, which plays an important role in gluconeogenesis: the conversion
of various non-carbohydrate substances into glucose for subsequent use.
Manganese is also involved in the transfer of high energy
phosphate groups by phosphotransferase enzymes. These enzymes are found in
various metabolic pathways, including several steps of glycolysis.
Manganese tends to activate the lipid metabolizing enzyme
lipoprotein lipase, otherwise called the "clearing factor."
Manganese seems to be important for the enzymatic
activity of glycosyltransferases, which play a vital role in mucopolysaccharide
synthesis. Impaired activity of these enzymes, due to manganese deficiencies,
can result in abnormal cartilage formation.
High calcium and phosphorus intake decreases manganese
Excretion of manganese is through the intestine via