Abstract:To explore whether carnosine can protect α-crystallin modification and decrease chaperone by a steroid, and whether carnosine could directly react with a steroid. · METHODS: Bovine lens α-crystallin was separated by size- exclusion chromatography on a Sephacyl S-300 HR column. α-Crystallin was incubated with different concentrations of prednisolone-21-hemisuccinate (P-21-H) with or without carnosine for different times. The chaperone activity of α-crystallin was monitored using the prevention thermal aggregation of α-crystallin. The modified α-crystallin was examined by SDS-PAGE and fluorescence measurements. The absorbance spectra of solutions of carnosine and P-21-H were investigated. · RESULTS: P-21-H decreased the chaperone activity of α-crystallin in a concentration- and time-dependent fashion. Carnosine only worsened this effect. The tryptophan fluorescence intensity of α-crystallin modified by P-21-H was significantly decreased compared with unmodified crystallin, whereas its non-tryptophan fluorescence was increased with a shift to longer wavelengths in a time- and dose-dependent manner, suggesting that new fluorophores were possibly formed. Carnosine readily reacted with P-21-H thereby inhibiting steroid-mediated protein modification as revealed electrophoretically. The increased absorbance was time-dependent, suggesting adducts may be formed between carnosine and P-21-H. · CONCLUSION: Carnosine reacts with P-21-H, which suggests carnosine's potential as a possible anti-steroid agent.
