For many years, clinical studies have suggested that blood levels of l-methionine and L-homocysteine correlate with health status or homocystinuria/hypermethioninemia. l-Methionine in a solution containing 0%, 10%, or 20% human serum was detected in 10-200 µM using l-methionine decarboxylase (MetDC). Spike and recovery tests showed that the enzymatic assay could accurately and reproducibly determine the increases in l-methionine in serum samples. These results suggest that our enzymatic method using MetDC is useful for primary screening of hypermethioninemia or homocystinuria based on serum l-methionine concentration. Additionally, we confirmed that l-methionine (100 nmol) in solution was degraded to less than the detection limit by incubation at 37ºC for 10 min using 2 U of MetDC. Therefore, l-homocysteine in serum samples can be detected with equivalent sensitivity using l-methionine γ-lyase (MGL), in solutions that either did not contain l-methionine or contained l-methionine preincubated with MetDC.Abbreviations: DTT: dithiothreitol; IPTG: isopropyl-β-d-thiogalactopyranoside; KPB: potassium phosphate buffer; MBTH: 3-methyl-2-benzothiazolinonehydrazone; mdc: the gene coding l-methionine decarboxylase; MetDC: l-methionine decarboxylase; mgl: the gene coding l-methionine γ-lyase; MGL: l-methionine γ-lyase; PLP: pyridoxal 5'-phosphate.

中文翻译：

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使用l-蛋氨酸脱羧酶测定l-蛋氨酸的新方法，以及该酶在l-高半胱氨酸测定中的应用。

多年来，临床研究表明，L-蛋氨酸和L-高半胱氨酸的血液水平与健康状况或高半胱氨酸尿症/高蛋氨酸血症有关。使用L-蛋氨酸脱羧酶（MetDC）在10-200 µM中检测到含有0％，10％或20％人血清的溶液中的L-蛋氨酸。峰值和回收率测试表明，酶法可以准确，可重复地测定血清样品中L-蛋氨酸的含量。这些结果表明，我们使用MetDC的酶法可用于基于血清L-蛋氨酸浓度的高蛋氨酸或高半胱氨酸尿的初步筛查。此外，我们证实了通过使用2 U MetDC在37ºC下孵育10分钟，溶液中的L-蛋氨酸（100 nmol）降解至检测限以下。因此，在不含L-蛋氨酸的溶液中或含有经MetDC预孵育的L-蛋氨酸的溶液中，可以使用L-蛋氨酸γ-裂合酶（MGL）以相同的灵敏度检测血清样品中的L-高半胱氨酸。IPTG：异丙基-β-d-硫代吡喃半乳糖苷；KPB：磷酸钾缓冲液；MBTH：3-甲基-2-苯并噻唑啉酮hydr；mdc：编码1-甲硫氨酸脱羧酶的基因；MetDC：1-甲硫氨酸脱羧酶；mgl：编码1-甲硫氨酸γ-裂解酶的基因；MGL：l-蛋氨酸γ-裂解酶；PLP：吡ido醛5'-磷酸盐。3-甲基-2-苯并噻唑啉酮hydr; mdc：编码1-甲硫氨酸脱羧酶的基因；MetDC：1-甲硫氨酸脱羧酶；mgl：编码1-甲硫氨酸γ-裂解酶的基因；MGL：l-蛋氨酸γ-裂解酶；PLP：吡ido醛5'-磷酸盐。3-甲基-2-苯并噻唑啉酮hydr; mdc：编码1-甲硫氨酸脱羧酶的基因；MetDC：1-甲硫氨酸脱羧酶；mgl：编码1-甲硫氨酸γ-裂解酶的基因；MGL：l-蛋氨酸γ-裂解酶；PLP：吡ido醛5'-磷酸盐。