Glycoenzymes carbohydrate components

The purification of many enzymes has been achieved by use of gel-filtration chromatography, ion-exchange chromatography, or other chromatographic procedures. Eluates from such columns may be analyzed for carbohydrate and protein content, as well as for enzymic activity. Such analyses have revealed that, for glycoenzymes, the enzymic activity, the carbohydrate content, and the protein content are distributed identically in the eluates from the columns. Results of this type of experiment for ribonuclease B are shown in Fig. 1. In these experiments,8 ribonuclease B and a hydrolyzate of the enzyme were subjected to gel filtration on Sephadex, and the eluates were analyzed for protein and for carbohydrate by appropriate colorimetric methods. A control experiment containing ribonuclease A and D-man-nose was treated similarly. The data in Fig. 1 show that the carbohydrate component in the unhydrolyzed sample of ribonuclease B... 

Centrifugation data from measurements with an analytical ultracentrifuge are useful for characterizing glycoenzymes. Pure gly-coenzymes yield symmetrical patterns when examined by this procedure. Sedimentation measurements can be made at several concentrations of the enzyme, and a number of physical constants characteristic of the molecule can be calculated from these data. On the basis of such measurements and calculations, it was determined that chloroperoxidase, which contains carbohydrate, is homogeneous with respect to molecular size,21 and it was concluded that the carbohydrate component in the preparation of chloroperoxidase studied is chemically linked to the protein. 

The second method of enzyme electrode preparation is based on the immobilization of glycoenzymes via their glycosidic component [178]. Here the carbohydrate moiety of glycoenzymes is activated by a periodate oxidation cleavage of vicinal diols of the carbohydrate units. The... 

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