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Updated: Jan 7, 2026

Application of AlDeSense to Stratify Ovarian Cancer Cells Based on Aldehyde Dehydrogenase 1A1 Activity
Published on: March 31, 2023
Structural diversity of aldehydes determines covalent versus non-covalent inhibition mechanisms against steroid
Junying Chen1, Shufang Qi1, Zijian Lin1
1Department of Anesthesiology and Perioperative Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; Key Laboratory of Precision Anesthesiology of Zhejiang Province, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China; Key Laboratory of Environment and Male Reproductive Medicine of Wenzhou, Wenzhou, Zhejiang, 325000, China.
Abstract:
Steroid 5α-reductase type 1 (SRD5A1) plays a crucial role in neurosteroid biosynthesis, and its inhibition by environmental chemicals may disrupt brain function. This study systematically evaluated the inhibitory effects of thirteen structurally diverse aldehydes on human and rat SRD5A1 activity using microsomal enzyme assays, surface plasmon resonance (SPR) binding, cellular experiments, and computational analyses. Three aldehydes significantly inhibited human SRD5A1: o-phthalaldehyde (OPA, IC50 = 2.74 μM), benzaldehyde (BEA, IC50 = 45.97 μM), and cinnamaldehyde (CNA, IC50 = 67.85 μM). Remarkable mechanistic differences were revealed through SPR analysis: OPA demonstrated covalent binding with incomplete dissociation (KD = 2.16 μM), while BEA showed complete dissociation characteristic of non-covalent binding (KD = 35.1 μM). All active compounds exhibited mixed/noncompetitive inhibition mechanisms. Species-specific differences were observed, with only OPA showing cross-species activity against rat SRD5A1. Cellular experiments revealed different potency patterns, with CNA demonstrating the strongest cellular effects despite weaker enzyme inhibition. Molecular docking revealed that OPA forms covalent bonds with Cys124 through Michael addition (-6.52 kcal/mol), while BEA and CNA rely on non-covalent interactions. DTT rescue experiments confirmed the covalent nature of OPA inhibition and the non-covalent mechanisms of BEA. OPA also uniquely affected NADPH binding kinetics, indicating its binding site spans both substrate and cofactor regions. 3D-QSAR modeling of non-covalent inhibitors identified hydrogen bond acceptor and hydrophobic features as critical for inhibition. These findings demonstrate that aldehyde structural diversity-particularly the presence of dual versus single aldehyde groups, determines both binding mechanisms and inhibitory potency, with important implications for environmental health risk assessment.
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