Tamaki Fabio Kendi
University of Dundee, Dundee, United Kingdom.
Biosci Rep. 2021 Nov 22. doi: 10.1042/BSR20211524.
The analysis of the urine contents can be informative of physiological homeostasis, and it has been speculated that the levels of urinary D-serine (D-ser) could inform about neurological and renal disorders. By analysing the levels of urinary D-ser using a D-ser dehydratase (DSD) enzyme, Ito et al. have described abundant levels of L-β-EHAsn, a non-proteogenic amino acid which is also a newly described substrate for DSD. The data presented supports the endogenous production L-β-EHAsn, with its concentration significantly correlating with the concentration of creatinine in urine. Taken together, these results could raise speculations that L-β-EHAsn might have unexplored important biological roles. It has been demonstrated that L-β-EHAsn also inhibits serine racemase with Ki values (40 μM) similar to its concentration in urine (50 μM). Given that serine racemase is the enzyme involved in the synthesis of D-ser, and L-β-EHAsn is also a substrate for DSD, further investigations could verify if this amino acid would be involved in the metabolic regulation of pathways involving D-ser.
对尿液成分的分析可以反映生理稳态，并且据推测，尿液中D-丝氨酸（D-ser）的水平可以反映神经和肾脏疾病。通过使用D-丝氨酸脱水酶（DSD）分析尿液中D-丝氨酸的水平，伊藤等人发现了大量的L-β-EHAsn，这是一种非蛋白质氨基酸，也是一种新发现的DSD底物。所呈现的数据支持L-β-EHAsn的内源性产生，其浓度与尿液中肌酐的浓度显著相关。综合来看，这些结果可能引发推测，即L-β-EHAsn可能具有尚未被探索的重要生物学作用。已经证明，L-β-EHAsn也以与尿液中浓度（50μM）相似的Ki值（40μM）抑制丝氨酸消旋酶。鉴于丝氨酸消旋酶是参与D-丝氨酸合成的酶，并且L-β-EHAsn也是DSD的底物，进一步的研究可以验证这种氨基酸是否参与涉及D-丝氨酸的代谢途径的调节。
