Insulin is a hormone that is needed for kreb cycle to function properly. In metabolism of glucose are three steps:

1. glycolysis in which the glucose is converted to pyruvate

2. kreb's cycle - pyruvate is converted to oxaloacetate by pyruvate carboxylase enzyme.

3. Electron transport chain.

In diabetes when there is deficiency of insulin, kreb's cycle won't work properly and thus the end product of glycolysis i.e pyruvate will be in excess in blood. Excess of pyruvate will lead to deficiency of pyruvate carboxylase which will lead to lactic acidosis. Also in case of anaerobic condition, the pyruvate will be converted to lactate.

pyruvate carboxylase and phosphoenolpyruvate carboxykinase (PEPCK)

PKD is caused by a deficiency in the enzyme, pyruvate kinase.

Pyruvate kinase deficiency (PKD) is part of a group of disorders called hereditary nonspherocytic hemolytic anemias.

Oxaloacetic acid is also produced when pyruvate is acted upon by pyruvate carboxylase in response to an excess of acetyl-CoA.