The amino acid which serves as a carrier of ammonia from skeletal muscle to liver is
GLUCOSE-ALANINE CYCLE 1. Skeletal muscle transpos NH3 to the Liver in the form of the amino acid 'alanine'. The alanine is formed in the muscle tissue by a transamination reaction between pyruvate (PA) and glutamate. 2. The alanine is transpoed through the bloodstream to the liver, where it reacts with a-ketoglutarate to reform Pyruvate and glutamate. This reaction is catalysed by alanine transaminase. 3. The nitrogen originating from the glutamate is processed by the urea cycle. 4. When the blood glucose is low, the Pyruvate resulting from alanine transamination is used to make glucose the gluconeogenesis pathway. 5. The glucose can be returned to the skeletal muscle to supply quick energy. Thus, the transpo of alanine from muscle to Liver results in a reciprocal transfer of glucose to muscle. The entire cyclical process is referred to as the "glucose-alanine cycle" (Fig. 27.5). Its impoance is propoional to the muscular activity of the organism. It is to be noted that active muscle tissue operates anaerobically, producing large quantities of Pyruvate (PA) and consuming large quantities of glucoseRef: M.N. Chatterjea - Textbook of Biochemistry, 8th edition, page no: 483
Alanine
Methionine
Arginine
Glutamine
Metabolism of protein and amino acid