ENZYME PATTERNS IN HUMAN TISSUES. 3. GLYCOLYTIC ENZYMES IN NORMAL AND MALIGNANT TISSUES OF THE COLON AND RECTUM.

Abstract

Summary Enzyme patterns for the glycolytic enzymes in human carcinoma of the colon and rectum are presented and compared with the patterns of the corresponding nonmalignant counterparts. Rectal and colon carcinomas, though similar, were treated separately because in general rectal carcinomas contain a higher proportion of malignant cells. The data presented indicate that the enzyme patterns of the various segments of the unaffected colon are similar. The relative patterns of the mucosal and smooth muscle elements of both colon and rectum were alike, but with respect to the absolute activities, the enzymes of the mucosal tissue were approximately 1.5-fold higher than those found in the undissected colon or rectum. The activities of the enzymes of the straight glycolytic pathway (except for phosphofructokinase) in the rectal and colon carcinomas were 2.5-fold greater than those of apparently uninvolved colon and rectal tissues and 1.7-fold greater than those of the mucosal elements. The most pronounced difference between the malignant and nonmalignant tissues was the decreased α-glycerolphosphate dehydrogenase activity in the tumors. Also decreased on a relative but not absolute basis were fructose-1,6-diphosphatase, and phosphofructokinase. The extent of the increased glycolytic capacity of the tumors is limited by phosphofructokinase, and alterations in the activity of this enzyme could profoundly influence the glycolytic rate.