Sustaining S‐adenosyl‐l‐methionine‐dependent methyltransferase activity in plant cells

Many biochemical reactions in plants involve the transfer of a methyl group from S ‐adenosyl‐ l ‐methionine (SAM). The transfer of the methyl group from SAM generates S ‐adenosyl‐ l ‐homocysteine (SAH), a potent inhibitor of SAM‐dependent methyltransferases (MTs). To mitigate the toxic effects of SAH on MT activity, SAH is removed by SAH hydrolase (SAHH, EC 3.3.1.1) in a reaction generating homocysteine and adenosine (Ado). However, SAHH …