Structural aspects on rat liver S-adenosylmethionine synthesis

Abstract

Methionine adenosyltransferase is the enzyme that catalyzes the synthesis of S-adenosylmethionine. In mammals three isoenzymes have been purified, two of which. MAT III and I, are products of the same gene MAT1A, but differ in their kinetic constants and oligomerization state. Changes in activity and MAT I/III ratio have been detected in animal models and in human alcohol liver cirrhosis, leading to an increasing interest in the mechanisms that control the protein association state. In this line, data demonstrating the importance of sulfhydryl groups on the activity and oligomerization of the protein have been obtained. These results along with knowledge of the crystal structure of MAT I and the establishment of an overall-folding pathway allow an integrated view for MAT behaviour.