Normally, the prothrombin precursor undergoes post-translational carboxylation (addition of a carboxylic acid group) by gamma-glutamyl carboxylase in the liver prior to secretion into plasma.
Additionally, a loss of pyruvate carboxylase allows potentially toxic compounds such as lactic acid and ammonia to build up and damage organs and tissues.
The majority of the enzymes responsible for gluconeogenesis are found in the cytoplasm; the exceptions are mitochondrial pyruvate carboxylase and, in animals, phosphoenolpyruvate carboxykinase.