The use of SAM synthetase from E.coli in the synthesis of SAM suffers severe problem in product inhibition, thus the SAM synthetase from E.coli is not suitable for large-scale synthesis of SAM.

• Matos等对不同种类SAM合成酶的活力的进行了比较：大肠杆菌SAM合成酶进行酶促反应会出现产物抑制问题，因此不太适合用来大规模生产SAM；