Argininosuccinate synthetase is an enzyme that plays a crucial role in the urea cycle, a metabolic pathway that helps remove ammonia from the body. It catalyzes the reaction between citrulline and aspartate to form argininosuccinate, which is an important intermediate in the synthesis of arginine and the excretion of nitrogen. This enzyme is primarily found in the liver, where it helps maintain nitrogen balance. Deficiencies in argininosuccinate synthetase can lead to a rare genetic disorder known as citrullinemia, which can cause serious health issues due to the accumulation of toxic substances in the body.