For instance, catechol-O-methyltransferase, which belongs to SAM-dependent methyltransferase fold family [44], could methylate catechol compounds and inactivate the catechol neurotransmitter dopamine in the prefrontal cortex [45], thus it has many a times been suggested to be involved in affective disorders, such as depression [46]. This evidence concerns the gene THUMPD2 and depressive symptom measurement.