Glutathione disulfide injection

Insulin is removed from the circulation by the liver and the kidney. The disulfide connections between the A and B chains are hydrolyzed through the action of glutathione insulin trans-hydrogenase. After this cleavage further degradation occurs by proteolysis. In patients treated with subcutaneous insulin injections the clearance by the liver is 40% and by the kidney 60%. The half-life of circulating insulin is 3-5 min. 

The structure of the hormone insulin (many diabetics lack this hormone and must inject themselves with it daily) was deduced in the 1950s by Sanger. It has two peptide chains, one of 21 amino acids and one of 30, linked by three disulfide bridges—just like the links in oxidized glutathione. This is a very small protein. 

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