RESUMO
In this paper, the use of tyrosinase (Ty) from Streptomyces antibioticus, labeled with a fluorescent tag, in combination with soluble quinoprotein (PQQ-containing) glucose dehydrogenase (s-GDH) to measure trace amounts of phenols is explored. Proof of concept is provided by a series of experiments, which show a clear quantitative dependence of the response on the phenol concentration. One of the advantages of the detection system is that apart from a standard fluorimeter no further instrumentation is required.
Assuntos
Glucose Desidrogenase/química , Metaloproteínas/química , Monofenol Mono-Oxigenase/química , Fenóis/química , Técnicas Biossensoriais , Eletroquímica , Enzimas Imobilizadas , Concentração de Íons de HidrogênioRESUMO
A new, fast, simple and cost-effective sensing device for monitoring H(2)S has been developed. Proof-of-principle results showing that a commercial and cheap Myoglobin (Mb) can be successfully used as a biological probe for a fluorescence biosensor for H(2)S detection are reported. The two different commercial labels Cy3 and Atto620 were selected for this study. A high selectivity for detecting H(2)S against other thiols was found. The applicability of the proposed sensing system was successfully explored not only in solution but also when applied in the form of a solid state device.
Assuntos
Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Mioglobina/química , Animais , Carbocianinas/química , Transferência Ressonante de Energia de Fluorescência , Proteínas Imobilizadas/química , TemperaturaRESUMO
In this paper we explore the use of fluorescently labeled cytochrome c peroxidase (CcP) from baker's yeast for monitoring nitric oxide (NO) down to the sub-micromolar level, by means of a FRET (Förster Resonance Energy Transfer) mechanism. The binding affinity constant (K(d)) for the NO binding to CcP was determined to be 10+/-1.5 microM. The rate of NO dissociation from the CcP (k(off)) and the second order rate constant for the NO association (k(on)) were found to be 0.22+/-0.08 min(-1) and 0.024+/-0.002 microM(-1) min(-1) respectively. The immobilization of fluorescently labeled CcP into a polymeric matrix for use in a solid state NO sensing device was also explored. The results provide proof-of-principle that labeled CcP can be successfully implemented in a fast, simple, quantitative and sensitive NO sensing device.