This is our fifth consecutive study carried out in an order to collect experimental evidence on the impact of heavy water (D₂O) on the spontaneous peptidization of proteinogenic α-amino acids and this time its subject matter is L-alanine (L-Ala). Our four earlier studies have been focused on the two sulfur-containing α-amino acids (i.e., L-cysteine (L-Cys) and L-methionine (L-Met)), and on two structurally related α-amino acids (i.e., L-proline (L-Pro) and L-hydroxyproline (L-Hyp)). It seemed interesting to assess the effect exerted by D₂O on L-Ala, the simplest chiral (endogenous and proteinogenic) α-amino acid with as low molar weight, as 89.09 g mol⁻¹ only. As analytical techniques, we used high-performance liquid chromatography with the diode array detection (HPLC–DAD), mass spectrometry (MS), and scanning electron microscopy (SEM). The obtained results make it clear that the impact of heavy water on the dynamics of the spontaneous peptidization of L-Ala is even stronger than with the four other α-amino acids discussed earlier (although in all five cases, heavy water significantly hampers spontaneous oscillatory peptidization). Unlike in the four previous cases, though, the solubility of L-Ala in pure D₂O is quite low and it takes twice as much time to dissolve it in D₂O than in MeOH + X, 70:30 (v/v). Consequently, the peptidization of L-Ala in heavy water is even more obstructed than it was the case with the other investigated α-amino acids and it results in considerable yields of the L-Ala crystals (most probably at least partially deuterated) at the expense of the L-Ala-derived peptides. Perhaps it might be interesting to add that out of five α-amino acids investigated so far, which can be divided into two groups of endogenous and exogenous species, two endogenous species (L-Cys and L-Pro) undergo spontaneous oscillatory peptidization in an aqueous-organic solvent (i.e., in the absence of D₂O) following the circadian rhythm, whereas two exogenous ones (i.e., L-Met and L-Hyp) do not. The third endogenous species (L-Ala) first undergoes two initials oscillations which are damped (not periodic) and the oscillatory changes are on a scale of ca. 10 h (as estimated with use of the Fourier transform approach) and after that, the system reaches a steady state.

这是我们连续进行的第五次研究，目的是收集重水（D ₂ O）对蛋白原性α-氨基酸自发肽化的影响的实验证据，这次的主题是L-丙氨酸（L-Ala ）。我们的四项早期研究集中于两种含硫的α-氨基酸（即L-半胱氨酸（L-Cys）和L-蛋氨酸（L-Met）），以及两种与结构相关的α-氨基酸（即，L-脯氨酸（L-Pro）和L-羟脯氨酸（L-Hyp））。评估D ₂ O对L-Ala的作用似乎很有趣，L-Ala是分子量低至89.09 g mol ^-1的最简单的手性（内源性和蛋白源性）α-氨基酸只要。作为分析技术，我们将高效液相色谱与二极管阵列检测（HPLC-DAD），质谱（MS）和扫描电子显微镜（SEM）结合使用。获得的结果清楚地表明，重水对L-Ala自发肽化动力学的影响甚至比之前讨论的其他四种α-氨基酸还要强（尽管在所有这五种情况下，重水都严重阻碍了自发振荡肽化）。但是，与之前的四种情况不同，L-Ala在纯D ₂ O中的溶解度非常低，将其溶解在D ₂ O中的时间是在MeOH + X中的70:30（v / v）。因此，与其他研究的α-氨基酸相比，重水中L-Ala的肽化过程甚至受阻更大，并且在L-Ala晶体处产生了可观的产量（最可能至少部分氘化了）。 L-Ala衍生肽的费用。也许有趣的是，到目前为止已研究的5种α-氨基酸可分为两类：内源性和外源性物种，其中两个内源性物种（L-Cys和L-Pro）在自然界中经历自发振荡的肽化作用。水性有机溶剂（即不存在D ₂O）遵循昼夜节律，而两个外生节奏（即L-Met和L-Hyp）则不然。第三种内源物质（L-Ala）首先经历了两个初始振动，这些振动被阻尼（不是周期性的），并且振荡变化的范围约为。10小时（使用傅立叶变换方法估算），然后系统达到稳定状态。