Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Faculty of Chemistry, Silesian University of Technology, Gliwice, Poland.
Biotechnology Centre, Silesian University of Technology, Gliwice, Poland.
J Sci Food Agric. 2021 Dec;101(15):6533-6541. doi: 10.1002/jsfa.11325. Epub 2021 Jun 1.
Oilseed rape is one of the most important oilseed crops worldwide, crucial in the food and feed industries. Different environment and climatic conditions can influence its sustainable cultivation and crop yield. Aminopeptidases are crucial enzymes in many physiological processes in all organisms, including humans, so it is important to learn their behavior in food and feed sources. This study presents, for the first time, a detailed discussion on the importance of aminopeptidases, during the oilseed rape germination process, under standard and stress conditions.
During the germination of oilseed rape under standard conditions, a significant increase in aminopeptidases activity toward N-terminal amino acids - phenylalanine (Phe), alanine (Ala), glycine (Gly), leucine (Leu), proline (Pro), methionine (Met) - was observed. The change was substrate specific, with the highest increase being observed for Gly (3.2-fold), followed by Ala (2.9-fold), Pro (2.5-fold), Met (1.5-fold), and Phe (1.3-fold). Generally, N-terminal Phe was preferentially cleaved. Germination under stress conditions, caused by several heavy metal ions (e.g. divalent copper, zinc, cadmium, and lead ions), negatively influenced the plants' growth and quality, but significantly enhanced the expression of genes encoding aminopeptidases (or potentially activated aminopeptidases precursors), which was related to the dramatic increase of their activity.
The activity/concentration of aminopeptidases in plants is adjusted to the needs at each stage of development and stress factors occurrence. The most significant increase of activity toward N-terminal Gly and Pro proved the key role of aminopeptidases in the defense mechanisms, by supplying the plants with osmoprotectants and organic nitrogen. The results provide new concepts of oilseed rape growth and cultivation under different conditions. © 2021 Society of Chemical Industry.
油菜是世界上最重要的油料作物之一，在食品和饲料工业中至关重要。不同的环境和气候条件会影响其可持续种植和作物产量。氨肽酶是所有生物体（包括人类）许多生理过程中的关键酶，因此了解它们在食物和饲料来源中的行为非常重要。本研究首次详细讨论了在标准和胁迫条件下，油菜发芽过程中氨肽酶的重要性。
在标准条件下油菜发芽过程中，对 N 末端氨基酸 - 苯丙氨酸（Phe）、丙氨酸（Ala）、甘氨酸（Gly）、亮氨酸（Leu）、脯氨酸（Pro）、蛋氨酸（Met）的氨肽酶活性显著增加。这种变化具有底物特异性，其中 Gly 的增加幅度最大（3.2 倍），其次是 Ala（2.9 倍）、Pro（2.5 倍）、Met（1.5 倍）和 Phe（1.3 倍）。通常，优先切割 N 末端的 Phe。几种重金属离子（如二价铜、锌、镉和铅离子）胁迫条件下的发芽会对植物的生长和品质产生负面影响，但会显著增强编码氨肽酶的基因的表达（或潜在激活的氨肽酶前体），这与它们活性的急剧增加有关。
植物中氨肽酶的活性/浓度是根据每个发育阶段和应激因素发生的需要进行调整的。对 N 末端 Gly 和 Pro 的活性增加最大，证明了氨肽酶在防御机制中的关键作用，为植物提供了渗透保护剂和有机氮。这些结果为不同条件下油菜的生长和种植提供了新概念。© 2021 化学工业协会。
