Oxidative stress biomarkers are powerful endpoints in toxicological research. Cellular reductive/oxidative balance affects numerous signaling pathways involving H₂O₂. Detoxification and control of H₂O₂ levels results mainly from catalase activity.

The aim of this work was to develop a precise, simple, cost-effective microassay to measure catalase activity in small tissue samples and cell extracts.

We developed a protocol that quantifies H₂O₂ decomposition by intrinsic catalase in biological samples. Catalase activity was calculated based on rate of decomposition of H₂O₂, following absorbance at 240 nm. We developed a multi-well spectroscopic approach, reducing sample quantity requirements and allowing simultaneous assessment of large number of samples.

The protocol is sensitive across a wide range of catalase activity (11.5–7575 U). The assay presents a 95% confidence interval with an intra-assay coefficient of variation of 3.7%, an inter-assay coefficient of variation of 6.2% and good correlation with a commercial kit. The assay was established and validated for different biological samples, including sheep hepatic tissue and human tumor and non-tumor cell lines.

This high-throughput method is robust, sensitive, time-saving and cost-effective, generating highly reproducible results with precision and good correlation with a commercial kit reinforcing the method's validity for research and toxicological applications.

氧化应激生物标志物是毒理学研究的有力终点。细胞还原/氧化平衡影响许多信号通路，包括 H ₂ O ₂。H ₂ O ₂水平的解毒和控制主要来自过氧化氢酶活性。

这项工作的目的是开发一种精确、简单、具有成本效益的微量测定法来测量小组织样本和细胞提取物中的过氧化氢酶活性。

我们开发了一个协议，通过生物样品中的内在过氧化氢酶来量化 H ₂ O ₂分解。过氧化氢酶活性根据H ₂ O ₂的分解速率在240 nm 处吸光度后计算。我们开发了一种多孔光谱方法，减少了样品数量要求并允许同时评估大量样品。

该协议对广泛的过氧化氢酶活性 (11.5–7575 U) 都很敏感。该测定具有 95% 的置信区间，测定内变异系数为 3.7%，测定间变异系数为 6.2%，与商业试剂盒具有良好的相关性。该测定针对不同的生物样本进行了建立和验证，包括绵羊肝组织和人类肿瘤和非肿瘤细胞系。

这种高通量方法稳健、灵敏、省时且具有成本效益，可产生高度可重复的结果，精度高，并且与商业试剂盒具有良好的相关性，增强了该方法在研究和毒理学应用中的有效性。