Chiral symmetry breaking in complex chemical systems with a large number of amino acids and a large number of similar reactions was considered. It was shown that effective averaging over similar reaction channels may result in very weak effective enantioselectivity of forward reactions, which does not allow most of the known models to result in chiral symmetry breaking during formation of life on Earth. Models with simple and catalytic synthesis of a single amino acid, formation of peptides up to length five, and sedimentation of insoluble pair of substances were considered. It was shown that depending on the model and the values of the parameters, chiral symmetry breaking may occur in up to about 10% out of all possible unique insoluble pair combinations even in the absence of any catalytic synthesis and that minimum total number of amino acids in the pair is 5. If weak enantioselective forward catalytic synthesis of amino acids is present, then the number of possible variants, in which chiral symmetry breaking may occur, increases substantially. It was shown that that the most interesting catalysts have zero or one amino acid of "incorrect" chirality. If the parameters of the model are adjusted in such a way to result in an increase of concentration of longer peptides, then catalysts with two amino acids of incorrect chirality start to appear at peptides of length five. Models of chiral symmetry breaking in the presence of epimerization were considered for peptides up to length three. It was shown that the range of parameters in which chiral symmetry breaking could occur significantly shrinks in comparison to previously considered models with peptides up to length two. An experiment of chiral symmetry breaking was proposed. The experiment consists of a three-step cycle: reversible catalytic synthesis of amino acids, reversible synthesis of peptides, and irreversible sedimentation of insoluble substances.

中文翻译：

---

地球生命形成过程中肽系统的手性对称性断裂。

考虑了在具有大量氨基酸和大量相似反应的复杂化学系统中的手性对称性破坏。结果表明，在相似反应通道上进行有效平均可能导致正向反应的有效对映体选择性非常弱，这不允许大多数已知模型导致地球生命形成过程中手性对称性的破坏。考虑了具有单个氨基酸的简单催化合成，至多五个长度的肽形成以及不溶性物质对沉淀的模型。结果表明，根据模型和参数值，即使在没有任何催化合成的情况下，在所有可能的独特不溶对组合中，多达约10％也会发生手性对称性断裂，并且该对中最小的氨基酸总数为5。如果弱对映选择性正向催化合成氨基酸如果存在α，那么可能发生手性对称性断裂的可能变体的数量大大增加。结果表明，最令人感兴趣的催化剂具有“不正确”手性的零个或一个氨基酸。如果以某种方式调整模型的参数以导致较长肽段的浓度增加，那么具有两个手性不正确氨基酸的催化剂就会出现在长度为5的肽段上。考虑到差向异构存在时手性对称性断裂的模型可用于长度不超过3的肽。结果表明，与先前考虑的最大长度为2的肽模型相比，可能发生手性对称性断裂的参数范围明显缩小。提出了一种手性对称性断裂的实验。实验包括三个步骤：氨基酸的可逆催化合成，肽的可逆合成以及不可溶物质的不可逆沉降。