Characterization of D-cysteine desulfhydrases and D-cysteine-containing compounds in plants

据文献记载，氨基酸通常以L-形式使用，并且参与其代谢的酶对L-对映体具有立体特异性。然而，D-氨基酸不仅存在于细菌中，也存在于其他生物体中，作为游离或共轭氨基酸以及肽的一部分。还表明，许多酶对各自的L-或D-型具有特异性。在细菌和植物中，D-半胱氨酸特异性的脱氢酶活性被证明催化D-半胱氨酸降解为丙酮酸、H2S和铵。我们希望表征来自植物的D-半胱氨酸脱氢酶的功能，以及随后的D-半胱氨酸和含D-半胱氨酸的肽在体内的作用。D-半胱氨酸可能参与特定的生物合成途径，蛋白质催化和信号传导过程。含D-半胱氨酸的多肽在植物-病原菌互作中可能发挥作用。将研究D-半胱氨酸和含D-半胱氨酸肽的代谢。在作物中，D-氨基酸的含量不同。一般的D-氨基酸和D-半胱氨酸对人体营养的影响还不清楚。减少D-半胱氨酸的百分比可能会改善植物性食品。

It is well documented that amino acids, in general, are used in the L-form, and that enzymes involved in their metabolism are stereospecific for the L-enantiomers. However, D-amino acids are found in bacteria, but also in other living organisms as free or conjugated amino acids and as part of peptides. It was also shown that many enzymes are specific for the respective L- or D-form. In bacteria and plants D-cysteine specific desulfhydrase activities were demonstrated catalysing the degradation of D-cysteine to pyruvate, H2S and ammonium. We would like to characterize the function of D-cysteine desulfhydrases from plants, and subsequently the role of D-cysteine and D-cysteine-containing peptides in vivo. D-cysteine might be involved in specific biosynthetic pathways, in protein catabolism and in signalling processes. D-cysteine containing peptides could play a role in plant-pathogen interaction. The metabolism of D-cysteine and D-cysteine-containing peptides will be investigated. In crop plants D-amino acids were found in different percentages. The influence of D-amino acids in general and D-cysteine specifically on human nutrition is not well understood. A reduction of the percentage of D-cysteine might improve plant-based food.