The main physiological function of sugar is to provide energy for life activities. Sugar catabolism is the main way for organisms to obtain energy. There are three main ways of oxidative decomposition of sugar in organisms: anaerobic oxidation of sugar, aerobic oxidation of sugar and pentose phosphate pathway.
Glycolysis refers to the process that glucose is decomposed into pyruvate in cytoplasm under anaerobic conditions. In this process, each molecule of glucose is decomposed to produce two molecules of pyruvate and two molecules of ATP, which belongs to a type of glucose metabolism. A ten-step reaction includes three key enzymes (rate-limiting enzymes): hexokinase, fructose-6-phosphate kinase and pyruvate kinase.
From 2065438 to 2009, it was found that tumor cells have different metabolic changes from normal cells, and tumor cells themselves can adapt to the changes of metabolic environment through the conversion between glycolysis and oxidative phosphorylation (OXPHOS).
Physiological significance of glycolysis
Glycolysis can convert the released free energy into ATP. Glycolysis is also a co-degradation pathway of hexose such as sugar, mannose and galactose. Fructose and mannose can be converted into fructose-6-phosphate under the catalysis of hexokinase, and fructose can also be converted into glyceraldehyde -3- phosphate through a series of enzymes.
Galactose can be converted into 1- glucose phosphate under the catalysis of some enzymes. Some congenital metabolic diseases are caused by the deletion of some enzymes in fructose and galactose metabolism. If fructose-phosphate aldolase is absent, the accumulation of fructose-1- phosphate in liver, intestine and kidney will cause hepatomegaly, and the absorption function of liver, kidney and intestine will decrease. Children with this disease should not take fructose or sucrose.
The above contents refer to Baidu Encyclopedia-glycolysis