Cadaverine modulates bovine alkaline phosphatase kinetics and structure: spectroscopic and bioinformatics study.

Enzyme stabilization is increasingly critical with the expanding industrial applications of enzymes. A major limitation in biotechnological processes is the poor stability of enzymes under harsh processing conditions. Natural osmolytes offer several advantages, including improved enzyme stability and solubility in hydrophobic environments. In this study, we examined the effect of cadaverine as an osmolyte on the stability and kinetics of bovine alkaline phosphatase (BALP). UV-Vis absorption measurements revealed hyperchromicity at 280 nm, indicating ground-state complex formation. Cadaverine binds BALP with moderate affinity (Kb = 5.42 × 10³ M⁻¹ at 298 K, n ≈ 1) via static quenching, KSV decreasing from 5.42 × 10³ to 4.31 × 10³ M⁻¹ as temperature rises from 298 to 318 K, and spontaneous, enthalpy-driven thermodynamics with ΔG° ≈ − 21 kJ mol⁻¹, ΔH° < 0, ΔS° < 0. It induces minor secondary-structure rearrangements (+ 4.5% α-helix, -4.2% β-sheet at 0.5 mM) while global fold remains unchanged (Rg 2.19–2.20 nm). Kinetic studies reveal mixed-type modulation with increased Km (0.60 to 0.99 mM) and Vmax at 0.5 mM cadaverine, yielding only ~ 27% higher catalytic efficiency. Docking and 40-ns MD confirmed peripheral binding dominated by electrostatic/H-bonding interactions near residues Asp42, Ser155, Asp316, and Glu430. Overall, cadaverine induces conformational changes in BALP and alters its kinetic parameters.