SHMT enzymatic preparation of L-ser requires THFA as its coenzyme, the enzyme SHMT is expressed by genetically engineered bacteria.Reduction of FA is the common synthetic method of THFA.

• 在利用基因工程菌表达的丝氨酸羟甲基转移酶（SHMT）酶法制备L-丝氨酸的过程中，SHMT需要四氢叶酸作为辅酶。