Plasma Glycoproteins in Malignant Disease

Abstract

In spite of the fact that plasma glycoproteins have recently been the subject of intense interest and investigation by clinically orientated biochemists,^10,11,13,14 knowledge of this ever expanding field has, as yet, received scant mention in clinical publications. The presence of free carbohydrate in the blood, largely in the form of glucose, has been recognized for years. However, an appreciation of the fact that hydrolysis of plasma protein releases additional reducing substances is of relatively recent origin,⁶ and the isolation and identification of these protein-bound sugars has been completed only in the last few years.^1,2,7,8 Such conjugated protein-carbohydrate complexes, when occurring in the plasma, are referred to as plasma glycoproteins. Six monosaccharides have been isolated and identified as forming the carbohydrate of the plasma glycoproteins.¹² These include galactose and mannose (the hexoses), glucosamine and galactosamine (which occur as N-acetyl derivatives and are collectively referred to as the