Mitochondrial 3-ketothiolase releases acetyl-CoA from acetoacetyl-CoA
and from 2-methylacetoacetyl-CoA, an intermediate in isoleucine
oxidation (see Chapter 156). Enzyme deficiency
can present in infancy with hyperammonemia, metabolic acidosis,
and severe ketosis, or later with fasting- or protein-induced episodes
of vomiting, hepatomegaly, ketoacidosis, and encephalopathy.