Antonio Cantero

Polysaccharides in Cancer: Glycoproteins and Glycolipids1

Publisher Summary Glycoproteins are usually defined as protein-carbohydrate complexes in which oligo- or polysaccharides are joined by covalent linkage to specific amino acids of proteins. List of well-defined Glycoproteins of animal origin is outlined in the chapter. Variations in the concentrations of serum glycoproteins have been implicated in a variety of diseased states and reviews on serum glycoproteins with respect to cancer have been performed. According to the recent work carried out on the biosynthesis of glycoproteins, it is believed that the polypeptide portion of protein undergoing synthesis is the receptor of N -acetyl hexosamine at the ribosomal level. The structures and the biosynthesis of these polysaccharides are mentioned in the chapter. It is revealed that the normal tissues and the tumor cells have some amount of glycoproteins. The chapter provides a brief review on miscellaneous investigations on glycoproteins and related observations. Mukerjee, Sri Ram, and Pierce studied a mucoprotein secreted by an epithelial tumor and characterized it as a counterpart of basement membrane of normal epithelium on the basis of histological, immunohistochemical, and electron microscopic observations. In a subsequent investigation, Pierce showed the synthesis of basement membranes by two breast carcinomas and a granulosa cell carcinoma grown in vitro .

Ribonucleases of rat liver: I. Partial purification and properties

Abstract Methods for the purification of both the acid and alkaline ribonucleases of rat liver are reported. It was possible to obtain a purified alkaline ribonuclease freed from acid ribonuclease activity. However, the preparation of acid ribonuclease was contaminated by the presence of alkaline ribonuclease activity. Some characteristics of both enzymes are reported. Preliminary results on the specificity of these enzymes showed that acid RNAase splits cyclic mononucleotides (purine or pyrimidine) whereas alkaline RNAase does not.

Polysaccharides In Cancer

Publisher Summary Polysaccharides, both free and associated with other body constituents, form a significant part of living cell. The diverse functions suggested for the polysaccharides range from their being an energy source (glycogen), blood group determinants (blood group polysaccharides), anticoagulants (heparins), structural material of ground substance and extracellular cement (mucoproteins), and secretions (mucoids) to being the components of certain hormones (glycoprotein hormones). A survey of literature has indicated that many of these polysaccharides are present in cancer tissues, animal as well as human. It is also found that certain transplantable animal hepatomas possess remarkable capacity to form and store glycogen. This chapter focuses on the homopolysaccharide-glycogen and discusses its general characteristics and isolation processes. It covers the detection of glycogen by histochemical, electron, microscopic, and radioautographic means, along with the biosynthesis of glycogen. It also outlines the research made in this field regarding the presence of glycogen in certain human tumors, including brain tumor, bone tumor, breast tumor, carcinoma of the bladder, and cancer of the cervix. The chapter also lists the effect of various cancer-causing agents on glycogen metabolism in liver, inlcuding X-irradiation, nitrosamines, ethionine, carbon tetrachloride, azo dyes, and aminofluorenes, and various studies that were conducted on glycogen in certain transplantable tumors. It studies the chemical composition and biosynthesis of major mucopolysaccharides—that is, heparin, hyaluronic acid, and chondroitin sulphates, and examines the effect of mucopolysaccharides on tumor growth.