title: [Resonance scattering spectral assay of papain enzymatic activity with sodium dodecyl benzene sulfonate].
abstract: 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. The scattering peak at 470 nm decreased with the activity of papain. The delta I470 value was linear with the papain activity in the range of 0.048-4.8 USP x mL(-1). Its regress equation is delta I(SDBS) = 1.972c + 2.31, with a related coefficient of 0.9999 and detection limit of 0.020 USP x mL(-1). This new assay has been applied to the assay of the papain activity in food additive with satisfactory results.
authors.affiliation: School of Environment and Resource, Guangxi Normal University, Guilin 541004, China.
authors.forename: Guo-xia
authors.initials: GX
authors.lastname: Huang
authors.forename: Zhi-liang
authors.initials: ZL
authors.lastname: Jiang
authors.forename: Ai-hui
authors.initials: AH
authors.lastname: Liang
authors.forename: Ye-cheng
authors.initials: YC
authors.lastname: Deng
mesh_terms: D055162:Biocatalysis; D010206:Papain / Q000032:analysis* / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D012967:Sodium Dodecyl Sulfate; D010206:Papain