The numerous and varied roles of phosphorylated organic molecules in biochemistry suggest they may have been important to the origin of life. The prominence of phosphorylated molecules presents a conundrum given that phosphorylation is a thermodynamically unfavorable, endergonic process in water, and most natural sources of phosphate are poorly soluble. We recently demonstrated that a semi-aqueous solvent consisting of urea, ammonium formate, and water (UAFW) supports the dissolution of phosphate and the phosphorylation of nucleosides. However, the prebiotic feasibility and robustness of the UAFW system are unclear. Here, we study the UAFW system as a medium in which phosphate minerals are potentially solubilized. Specifically, we conduct a series of chemical experiments alongside thermodynamic models that simulate the formation of ammonium formate from the hydrolysis of hydrogen cyanide, and demonstrate the stability of formamide in such solvents (as an aqueous mixture). The dissolution of hydroxylapatite requires a liquid medium, and we investigate whether a UAFW system is solid or liquid over varied conditions, finding that this characteristic is controlled by the molar ratios of the three components. For liquid UAFW mixtures, we also find the solubility of phosphate is higher when the quantity of ammonium formate is greater than urea. We suggest the urea within the system can lower the activity of water, help create a stable and persistent solution, and may act as a condensing agent/catalyst to improve nucleoside phosphorylation yields.

磷酸化有机分子在生物化学中的众多不同作用表明它们可能对生命的起源很重要。磷酸化分子的突出存在带来了一个难题，因为磷酸化是一种热力学上不利的水中吸能过程，而且大多数天然来源的磷酸盐都难溶。我们最近证明，由尿素、甲酸铵和水组成的半水溶剂（UAFW）支持磷酸盐的溶解和核苷的磷酸化。然而，UAFW 系统的益生元可行性和稳健性尚不清楚。在这里，我们研究了 UAFW 系统作为磷酸盐矿物质可能溶解的介质。具体来说，我们进行了一系列化学实验以及热力学模型，模拟氰化氢水解形成甲酸铵，并证明甲酰胺在此类溶剂（作为水性混合物）中的稳定性。羟基磷灰石的溶解需要液体介质，我们研究了 UAFW 系统在不同条件下是固体还是液体，发现这一特性是由三种组分的摩尔比控制的。对于液体 UAFW 混合物，我们还发现当甲酸铵的量大于尿素时，磷酸盐的溶解度更高。我们建议系统内的尿素可以降低水的活性，有助于形成稳定且持久的溶液，并且可以充当缩合剂/催化剂以提高核苷磷酸化产率。