Glutamine can serve as a source of energy for living cells. As represented in the figure, glutamine metabolism begins with its conversion to glutamate by the enzyme glutaminase. Glutamate is then converted to a-ketoglutarate by the enzyme glutamate dehydrogenase. Glutamine Glutaminase Glutamate Dehydrogenase Glutamate a-Ketoglutarate The product of the pathway represented in the figure most likely enters directly into which of the metabolic processes?