Precolumn derivatization LC/MS method for observation of efficient hydrogen sulfide supply to the kidney via...

d-Cysteine (d-Cys) is metabolized to hydrogen sulfide (H₂S) by d-amino acid oxidase (DAO)/3-mercaptopyruvate sulfurtransferase pathway. The pathway is required for H₂S supplementation that ameliorates acute kidney injury after the oral administration of d-Cys in mice. However, whether the rate-limiting activity of DAO regulates the tissue-selectivity or the extent of d-Cys degradation and H₂S supplementation remains unclear. Here, to analyze the levels of d-Cys and H₂S, we use two derivatization methods, a new method with no detectable isomerization of Cys and an established method for H₂S. The derivatives were determined by LC/MS using a C18 column. With the methods, we show that inhibition of DAO significantly suppresses the H₂S supplementation and d-Cys degradation in the mouse kidney. Additionally, we found that d-Cys is more efficiently metabolized into H₂S than l-Cys in the kidney. Our results reveal the utility of the method and support the advantage of d-Cys administration in improving the supply of H₂S to the kidneys.