Analysis of the role of sulfur amino acids metabolism in renal proximal tubules using mice lacking cysteine-producing enzymes

胱硫氨酸β-合成酶（CBS）和胱硫氨酸γ-裂解酶（CSE）是参与硫氨基酸代谢的转硫酶。缺乏cbs的患者表现出严重的临床症状，而缺乏cse的患者则被认为没有任何临床表现。虽然这两种酶主要在小鼠的肝脏和肾脏中表达，但它们在肾脏中的作用仍有待阐明。在cbs缺陷小鼠中，毒性蛋氨酸的尿排泄效率低得多，而在cse缺陷小鼠中，胱氨酸能有效地排泄到尿中。排泄效率被认为与症状的不同有关。在外观正常的cse缺乏小鼠中出现妊娠性高血压和蛋白尿。具有血管松弛活性的H2S已知由CBS和CSE产生，其在肾脏中的分布与这两种酶重叠。

Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are the transsulfuration enzymes that are involved in sulfur amino acids metabolism. CBS-deficient patients show severe clinical symptoms, while CSE-deficient persons are considered to be free of any clinical manifestations. Although both enzymes are primarily expressed in the liver and the kidney of mice, their roles in the kidney remain to be elucidated. In CBS-deficient mice, the urinary excretion of toxic methionine was much lower efficiency, while the cystathionine was efficiently excreted into the urine in CSE-deficient mice. The efficiency of excretion is considered to be related to the difference of symptoms. Pregnancy-induced hypertension and proteinuria was developed in normal-appearing CSE-deficient mice. H2S that has vasorelaxant activity is known to be produced by CBS and CSE, and its distribution was overlapped with both enzymes in kidney.