A 34-year-old woman with a history of malabsorption presents with progressive fatigue, paresthesias, and impaired wound healing over 3 months. Laboratory studies reveal low serum albumin and fat-soluble vitamin deficiencies. A muscle biopsy shows abnormal mitochondrial morphology and impaired oxidative metabolism. An investigator studying her metabolic dysfunction focuses on the first committed step of the citric acid cycle, where acetyl-CoA condenses with oxaloacetate to form citrate. This reaction is catalyzed by citrate synthase. Which of the following vitamins is an essential component of the cofactor required for this enzyme-catalyzed reaction?
- A)Thiamine (vitamin B1)
- B)Pantothenic acid (vitamin B5)GABARITO
- C)Cobalamin (vitamin B12)
- D)Niacin (vitamin B3)
- E)Riboflavin (vitamin B2)
Explicação
Pantothenic acid (vitamin B5) is the essential vitamin component of coenzyme A (CoA), the critical cofactor required for citrate synthase activity. In the citrate synthase reaction, acetyl-CoA (derived from acetyl group bound to CoA) reacts with oxaloacetate t... Ver explicação completa e trilha adaptativa →