title: Low-level chemiluminescence of N-beta-alanyl-L-histidine (L-carnosine).
abstract: Oxidized N-beta-Ala-L-His (L-carnosine) emitted low-level CL. The CL specificity was shown by experiments with L-carnosine from six separate vendors, several L-carnosine-like compounds, and nine different oxidizers. Purity of L-carnosine samples was analysed by RP-HPLC-MS, (1)H-NMR, MALDI-TOF-MS and ESI-MS. L-Carnosine CL magnitude varied with source; consequently, detection sensitivity was 5-100 nmol. CL of L-anserine (N-beta-Ala-1-methyl-L-His) was equal to or less than L-carnosine, depending upon oxidizer. H(5)IO(6) (2 mmol/L) in 11 mmol/L NaOH or 20 mmol/L K(3)Fe(CN)(6) + 10 mmol/L H(2)O(2) in 100 mmol/L NaOH were oxidizers of choice. Scavengers of (.)OH(-) radical quenched CL. Kinetic studies revealed a bi-phasic CL comprising a short-lived (<1 s) 'flash' and then prolonged ( approximately 2000 s) 'glow'. A structural basis and mechanism of L-carnosine CL are discussed. L-Carnosine CL could be useful for monitoring its level in biological samples.
authors.affiliation: ZymeTx Inc, 800 Research Parkway, Suite #100, Oklahoma City, OK 73104, USA. achyuthan@zymetx.com
authors.forename: K E
authors.initials: KE
authors.lastname: Achyuthan
mesh_terms: D000861:Anserine / Q000737:chemistry; D002336:Carnosine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D007202:Indicators and Reagents; D007700:Kinetics; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D016877:Oxidants; D010084:Oxidation-Reduction; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods
chemical_list: D007202:Indicators and Reagents; D016877:Oxidants; D002336:Carnosine; D000861:Anserine