Study Of Tyrosine On-Line Fluorescence Spectrum Under High Pressure

Study of the distribution of amino acids in seawater not only has great significance on the marine carbon and nitrogen in the geochemical cycle but also can explore the circulation of protein(amino acids) in marine food chain and clarify the source of protein in sediments.Detections of marine amino acids most commonly used are automatic analysis of amino acid analyzer, which the sample must be lower concentration. Therefore, the sample must be desalinated and enriched before detection, and this preprocessing are time-consuming and laborious. Fluorescence widely used in fluorescent substances in marine because of no pretreatment process. The fluorescence of fluorescent substances is not only related to the structure itself, and it also related to their environment, such as at different hydrostatic pressure the fluorescence spectrum of amino acid will be a significant change, different ion type and concentration will also affect fluorescence spectroscopy.As one of three natural fluorescent amino acid, tyrosine(Tyr) is the precursor of synthesis catecholamine neurotransmitters-dopamine, epinephrine and norepinephrine. Therefore, Tyr became more and more important in measures of nutritional interventions for improving the psychological and operational efficiency. So, in this paper, on the basis of reviews on the research of marine amino acids and basic principle high-pressure fluorescence, we studied the effect of pressure on fluorescence Spectrum of Tyr aqueous solution and Tyr in different concentrations of K+,Mg²⁺,Ni²⁺,Cu²⁺ on the conditions of pH of seawater and the pressure from atmospheric pressure to 60 MPa. Results showed:(1) Theλmax of Tyr aqueous solution had no change in our experiment conditions.(2) The fluorescence intensity of Tyr aqueous solution enhanced with increased hydrostatic pressure.(3) At atmospheric pressure, the fluorescence intensities of Tyr aqueous solution were constant in the presences of K+,Mg²⁺ but quenched obviously in the presences of Ni²⁺,Cu²⁺ where the quenching became stronger when the concentration increased.(4) The effect of pressure on the fluorescence intensity of Tyr aqueous solution was different in the presences of various Ni²⁺,Cu²⁺ concentrations, When Ni²⁺,Cu²⁺ concentration was lower, the fluorescence intensity increased relatively smaller and vice versa the fluorescence intensity increased relatively higher. The study of tryptophan fluorescence provide some reference value for the on-line research of the ocean dissolved protein and amino acids and the study of Tyrosine as exogenous or endogenous probes to explore protein conformational changes and also provide a new idea on exploring the mechanisms of deep-sea hydrothermal vents community resistant to high metal ion concentration.