Frömmel Jan, Šebela Marek, Demo Gabriel, Lenobel René, Pospíšil Tomáš, Soural Miroslav, Kopečný David
Department of Protein Biochemistry and Proteomics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, 783 71, Olomouc, Czech Republic.
Amino Acids. 2015 Jan;47(1):175-87. doi: 10.1007/s00726-014-1853-5. Epub 2014 Oct 26.
Plant aminoaldehyde dehydrogenases (AMADHs, EC 1.2.1.19) belong to the family 10 of aldehyde dehydrogenases and participate in the metabolism of compounds related to amino acids such as polyamines or osmoprotectants. Their broad specificity covers ω-aminoaldehydes, aliphatic and aromatic aldehydes as well as nitrogen-containing heterocyclic aldehydes. The substrate preference of plant AMADHs is determined by the presence of aspartic acid and aromatic residues in the substrate channel. In this work, 15 new N-acyl derivates of 3-aminopropanal (APAL) and 4-aminobutanal (ABAL) were synthesized and confirmed as substrates of two pea AMADH isoenzymes (PsAMADH 1 and 2). The compounds were designed considering the previously demonstrated conversion of N-acetyl derivatives as well as substrate channel dimensions (5-8 Å × 14 Å). The acyl chain length and its branching were found less significant for substrate properties than the length of the initial natural substrate. In general, APAL derivatives were found more efficient than the corresponding ABAL derivatives because of the prevailing higher conversion rates and lower K m values. Differences in enzymatic performance between the two isoenzymes corresponded in part to their preferences to APAL to ABAL. The higher PsAMADH2 affinity to substrates correlated with more frequent occurrence of an excess substrate inhibition. Molecular docking indicated the possible auxiliary role of Tyr163, Ser295 and Gln451 in binding of the new substrates. The only derivative carrying a free carboxyl group (N-adipoyl APAL) was surprisingly better substrate than ABAL in PsAMADH2 reaction indicating that also negatively charged aldehydes might be good substrates for ALDH10 family.
植物氨基醛脱氢酶（AMADHs，EC 1.2.1.19）属于醛脱氢酶第10家族，参与多胺或渗透保护剂等与氨基酸相关化合物的代谢。它们具有广泛的特异性，涵盖ω-氨基醛、脂肪族和芳香族醛以及含氮杂环醛。植物AMADHs的底物偏好由底物通道中天冬氨酸和芳香族残基的存在决定。在本研究中，合成了15种新的3-氨基丙醛（APAL）和4-氨基丁醛（ABAL）的N-酰基衍生物，并确认为两种豌豆AMADH同工酶（PsAMADH 1和2）的底物。这些化合物的设计考虑了先前证明的N-乙酰基衍生物的转化以及底物通道尺寸（5-8 Å×14 Å）。发现酰基链长度及其分支对底物性质的影响不如初始天然底物的长度显著。一般来说，由于普遍较高的转化率和较低的K m值，APAL衍生物比相应的ABAL衍生物更有效。两种同工酶之间的酶促性能差异部分与其对APAL和ABAL的偏好相对应。PsAMADH2对底物的较高亲和力与更频繁出现的过量底物抑制相关。分子对接表明Tyr163、Ser295和Gln451在新底物结合中可能起辅助作用。唯一带有游离羧基的衍生物（N-己二酰APAL）在PsAMADH2反应中出人意料地比ABAL是更好的底物，这表明带负电荷的醛也可能是ALDH10家族的良好底物。
