ABSTRACT
This chapter discusses possible metabolic interrelationships between the amino acids histidine and methionine. Cells require transport mechanisms for uptake of essential nutrients and excretion of metabolic waste products. Amino acids are transported by several specific carriers, which overlap somewhat in their specificities. Methionine (MET) and histidine (HIS) are both transported on the “leucine” carrier, also known as the “Large Neutral Amino Acid” carrier. The chapter examines the metabolic relationship between HIS and MET, particularly in the context of protein-energy malnutrition. The pathogenesis of protein-energy malnutrition (PEM) is complex and involves the major food nutrients as well as vitamin and mineral elements. One characteristic of PEM is its effects on plasma amino acid profiles. The most significant metabolic interaction between HIS and MET may be as follows: decreases in dietary MET cause decreased HIS catabolism due to a depletion of one-carbon receptor intermediates.
