</span>Folic acid is one of the vitamin B family as it was the B9 vitamin. Excess folate can mask the symptoms of B12 deficiency. Both folate and B12 have a role in red blood cell formation. Deficiency of those molecules will result in megaloblastic anemia where the red blood cells are too low but increased in size.
It depends on how it changes cause if it changes shape then the substrate might not be able to come to the active site inorder for the enzyme to work correctly.