The conversion requires the coenzyme thiamine pyrophosphate. There is tentative evidence that coenzyme Q10 reduces migraine frequency. Pantothenic acid is used in the synthesis of coenzyme A (CoA). In oxidation-reduction reactions, the active part of the coenzyme is the nicotinamide. PLP is a required coenzyme of glycogen phosphorylase, the enzyme necessary for glycogenolysis to occur. Metabolically-important species that include phosphorylated ribose include ADP, ATP, coenzyme A, and NADH. There is some evidence for the benefits of coenzyme Q10 in treating heart failure. This "cis-trans"-isomerase contains glutathione as a coenzyme. Fatty acids bound to coenzyme A to allow penetration into mitochondria. It is mainly utilized by organisms in the form of acetyl coenzyme A. Studies have shown that homocysteine reacts with SDH's PLP coenzyme to create a complex. Less severe cases present with metabolic disease associated with insufficient activity of the coenzyme PLP. Pyridoxal phosphate is required as a coenzyme. Steric hindrance is the major limiting factor in the synthesis of the coenzyme analogs. When bound to coenzyme A, it is central to the metabolism of carbohydrates and fats.