This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification and metabolism of amino acids, Subject name: Biochemistry
[{'content': 'Which of the following is elevated in Pyridoxal Phosphate deficiency? \nSelect and explain. \nA. FIGLU, B. Homocystine, C. Methylmalonic acid, D. Xanthurenic acid', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Xanthurenic acid >> Homocysteine (Both are increased in PLP deficiency) 3-OH Kynurenine is one of the intermediate in Tryptophan catabolism Normally conveed to next intermediate and this conversion requires vitamin B6/ PLP. But in B6 deficiency, 3-OH Kynurenine is diveed to form alternate metabolite= Xanthurenic acid (See fig) which is excreted in urine. Homocystine is a chemical compound consisting of two homocysteine molecules joined by a disulfide.', 'role': 'assistant'}]