[Fluorescence quenching assay of ultratrace horseradish peroxidase using rhodamine dye].

In acetate buffer solution, the reaction of H2O2 with KI was catalyzed by horseradish peroxidase (HRP) to form I3-. The I3- combined respectively with rhodamine S(RhS), rhodamine 6G(Rh6G), rhodamine B(RhB) and butyl-rhodamine B(b-RhB) to form RhS-I3, Rh6G-I3, RhB-I3 and b-RhB-I3 association particles, resulting in the fluorescence quenching at 580, 580, 554 and 554 nm, respectively. The effect of pH value, rhodamine dye concentration, KI concentration, H2O2 concentration, reaction temperature and time on the fluorescence quenching intensity (deltaF) of the four catalytic systems was considered respectively.

[Resonance scattering spectral assay of papain enzymatic activity with sodium dodecyl benzene sulfonate].

In pH 6.5 phosphate buffer solutions, dodecyl benzene sulfonate (SDBS) was combined with casein to form association particles, which exhibited five Rayleigh scattering peaks at 470, 360, 400, 420 and 520 nm, respectively. Under suitable conditions, papain has catalytic effect on the hydrolysis of casein, and SDBS can stop the catalytic reaction and be combined with the excess casein to form association particles.

Resonance scattering spectra of micrococcus lysodeikticus and its application to assay of lysozyme activity.

Background: Several methods, including turbidimetric and colorimetric methods, have been reported for the detection of lysozyme activity. However, there is no report about the resonance scattering spectral (RSS) assay, which is based on the catalytic effect of lysozyme on the hydrolysis of micrococcus lysodeikticus (ML) and its resonance scattering effect.

Results: ML has 5 resonance scattering peaks at 360 400, 420, 470, and 520 nm with the strongest one at 470 nm.