PATHWAYS OF OXALATE FORMATION FROM PHENYLALANINE, TYROSINE, TRYPTOPHAN AND ASCORBIC-ACID IN RAT
PATHWAYS OF OXALATE FORMATION FROM PHENYLALANINE, TYROSINE, TRYPTOPHAN AND ASCORBIC-ACID IN RAT
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DOI：
10.1016/0304-4165(77)90238-0
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发表时间：
1977-01-01
期刊：
影响因子：
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通讯作者：
RICHARDSON, KE
中科院分区：
文献类型：
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作者：
GAMBARDELLA, RL;RICHARDSON, KE
在雄性大鼠中研究了L-[14 C1]苯丙氨酸、L-[14 C1]酪氨酸、L-[14 C1]色氨酸和L-[14 C1]抗坏血酸转化为[14 C]草酸盐的代谢途径。在注射L-[14 C1]抗坏血酸的大鼠尿液中仅检测到[14 C]草酸盐，但从[14 C1]标记的芳香族氨基酸中回收了[14 C]标记的草酸盐、乙醇酸盐、乙醛酸盐、乙醇醛、甘氨酸和丝氨酸。DL-苯乳酸盐是乙醇酸氧化酶和乙醇酸脱氢酶的抑制剂，可减少给予[14 C1]-标记芳香族氨基酸的大鼠尿液中回收的[14 C]草酸盐的量，但可增加由L-[14 C1]-苯丙氨酸和L-[14 C1]酪氨酸形成的[14 C]乙醇酸盐的量以及由[14 C1]色氨酸产生的[14 C]乙醇酸盐的量。根据鉴别的[14 C]标记中间体和放射性的相对分布，推测苯丙氨酸和酪氨酸通过乙醇酸转化为草酸，乙醇酸通过乙醇酸脱氢酶直接氧化为草酸。色氨酸通过乙醛酸代谢，乙醛酸被乙醇酸氧化酶直接氧化为草酸。乙醇酸、乙醛酸、乙醇酸氧化酶或乙醇酸脱氢酶均不参与抗坏血酸草酸盐的形成。
The metabolic pathway by which L-[14C1]phenylalanine, L-[14C1]tyrosine, L-[14C1]tryptophan, and L-[14C1]ascorbic acid are converted to [14C]oxalate was investigated in the male rat. Only [14C]oxalate was detected in the urine of rats injected with L-[14C1]ascorbic acid, but [14C]-labeled oxalate, glycolate, glyoxylate, glycolaldehyde, glycine, and serine were recovered from the [14C1]-labeled aromatic amino acids. DL-Phenyllactate, an inhibitor of glycolic acid oxidase and glycolic acid dehydrogenase, reduced the amount of [14C]oxalate recovered in the urine of rats given the [14C1]-labeled aromatic amino acids, but increased the amount of [14C]glycolate formed from L-[14C1]-phenylalanine and L-[14C1]tyrosine and the amount of [14C]glycolate produced from [14C1]tryptophan. Based on the [14C]labeled intermediates identified and the relative distribution of the radioactivity, it was postulated that phenylalanine and tyrosine were converted to oxalate via glycolate which was oxidized directly to oxalate by glycolic acid dehydrogenase. Tryptophan was metabolized via glyoxylate which was oxidized directly to oxalate by glycolic acid oxidase. Neither glycolate, glyoxylate, glycolic acid oxidase or glycolic acid dehydrogenase were involved in the formation of oxalate from ascorbic acid.