題目血中同半胱胺酸(homocysteine)濃度過高是因何種胺基酸代謝異常所致?A.苯丙胺酸(phenylalanine)B.色胺酸(tryptophan)C.異白胺酸(isoleucine)D.甲硫胺酸(methionine)官方答案D