Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
Pharmacy Center, Institute of Biomedical Science, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
PLoS One. 2021 Jun 24;16(6):e0253608. doi: 10.1371/journal.pone.0253608. eCollection 2021.
Twelve carbonic anhydrase (CA) isoforms catalyze carbon dioxide hydration to bicarbonate and acid protons and are responsible for many biological functions in human body. Despite their vital functions, they are also responsible for, or implicated in, numerous ailments and diseases such as glaucoma, high altitude sickness, and cancer. Because CA isoforms are highly homologous, clinical drugs designed to inhibit enzymatic activity of a particular isoform, can also bind to others with similar affinity causing toxic side effects. In this study, the affinities of twelve CA isoforms have been determined for nineteen clinically used drugs used to treat hypertension related diseases, i.e. thiazides, indapamide, and metolazone. Their affinities were determined using a fluorescent thermal shift assay. Stopped flow assay and isothermal titration calorimetry were also employed on a subset of compounds and proteins to confirm inhibition of CA enzymatic activity and verify the quantitative agreement between different assays. The findings of this study showed that pharmaceuticals could bind to human CA isoforms with variable affinities and inhibit their catalytic activity, even though the drug was intended to interact with a different (non-CA) protein target. Relatively minor structural changes of the compounds may cause significant changes in affinity and selectivity for a particular CA isoform.
十二种碳酸酐酶（CA）同工酶催化二氧化碳水合生成碳酸氢根和质子酸，负责人体的许多生理功能。尽管它们具有重要的功能，但它们也与许多疾病有关，如青光眼、高原病和癌症。由于 CA 同工酶具有高度同源性，因此设计用于抑制特定同工酶酶活性的临床药物也可能以类似的亲和力与其他同工酶结合，从而导致毒性副作用。在这项研究中，测定了 19 种用于治疗高血压相关疾病的临床药物（即噻嗪类、吲达帕胺和美托拉宗）对十二种 CA 同工酶的亲和力。使用荧光热位移测定法测定了它们的亲和力。还在一组化合物和蛋白质上使用停流法和等温滴定量热法来确认 CA 酶活性的抑制作用，并验证不同测定之间的定量一致性。这项研究的结果表明，尽管药物旨在与不同的（非 CA）蛋白质靶标相互作用，但药物仍可能与人类 CA 同工酶以不同的亲和力结合并抑制其催化活性。化合物的相对较小的结构变化可能导致对特定 CA 同工酶的亲和力和选择性发生显著变化。
