GCAT is also known as KBL, aminoacetone synthase or 2-amino-3-ketobutyrate coenzyme A ligase and is a 419 amino acid protein. GCAT is localized to mitochondria in various tissues, including heart, brain, liver, pancreas and lungs. In mitochondria, two enzymes function in catalyzing the reaction that converts L-threonine into glycine, the second of which is GCAT. L-threonine is first converted into 2-amino-3-ketobutyrate by TDH, a reaction that is proceeded by the CoA- and GCAT-dependent formation of glycine and acetyl-CoA. Defects in the gene encoding GCAT may result in elevated levels of aminoacetone and carbon dioxide, both of which are products of the 2-amino-3-ketobutyrate intermediate and can further breakdown to form methylglyoxal, hydrogen peroxide and ammonia. Excess blood levels of methylglyoxal may cause kidney damage and are thought to be associated with diabetic complications.