Small molecule-ligands stabilized gold nanoclusters (AuNCs) have attracted increased attention in recent years in catalysis and colorimetric sensing field. However, the L-amino acid-ligands effect on boosting the catalytic activity of AuNCs has been rarely reported. In this work, four kinds of AuNCs were synthesized with L-alanine, L-asparagine, L-glutamic acid and L-arginine as the capping-ligand, respectively. Comparing with those AuNCs, L-alanine protected AuNCs (L-Ala@AuNCs) exhibited stronger peroxidase-like catalytic activity in the oxidation of 3,3′, 5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂ due to its shortest carbon chain and least steric hindrance. Particularly, epinephrine induced the blue reaction solution to wathet-blue with a good linear relationship between the color fading and the epinephrine concentration in a range from 0.4 to 25.0 μM (R²=0.993). The limit of detection was 0.2 μM. A colorimetric assay upon L-Ala@AuNCs-TMB-H₂O₂ system was developed for measurement of epinephrine content in medicine-injections with sensitivity and selectivity. The protocol paves a new way for enhancing the enzyme-like catalytic activity of AuNCs via ligand effect and shows a promising potential in bio-molecules and drugs colorimetric detection in real clinic samples.

近年来，小分子配体稳定的金纳米团簇（AuNCs）在催化和比色传感领域引起了越来越多的关注。然而，L-氨基酸配体对提高 AuNCs 催化活性的影响却鲜有报道。在这项工作中，分别以 L-丙氨酸、L-天冬酰胺、L-谷氨酸和 L-精氨酸作为封端配体合成了四种 AuNC。_{与那些 AuNCs 相比，L-丙氨酸保护的 AuNCs (L-Ala@AuNCs) 在 H 2} O ₂存在下氧化 3,3', 5,5'-四甲基联苯胺 (TMB) 时表现出更强的类过氧化物酶催化活性由于其最短的碳链和最小的空间位阻。特别地，肾上腺素诱导蓝色反应液呈深蓝色，褪色程度与肾上腺素浓度在0.4~25.0 μM范围内呈良好的线性关系（R ² =0.993）。检测限为 0.2 μM。_{开发了一种基于 L-Ala@AuNCs-TMB-H 2} O ₂系统的比色法，用于测定药物注射剂中肾上腺素的含量，具有灵敏度和选择性。该协议为通过配体效应增强 AuNC 的酶样催化活性开辟了一条新途径，并在实际临床样本中显示出生物分子和药物比色检测的巨大潜力。