Enzymatic activity of alkaline phosphatase adsorbed on dimyristoylphosphatidic acid Langmuir–Blodgett films

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 25; no. 2; pp. 119 - 128
• Main Authors: Caseli, Luciano, Zaniquelli, Maria Elisabete Darbello, Furriel, Rosa Prazeres Melo, Leone, Francisco Assis
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2002
• Subjects: Adsorption isotherm; Adsorption isotherms; Alkaline phosphatase; Dimyristoyl phosphatidic acid; Enzymatic catalysis; Hydrolysis; Langmuir Blodgett films; Langmuir monolayers; Micelles; Non-ionic surfactant; Quartz; Surface active agents; Surface reactions; Surface tension; Alkaline phosphatase; Enzymatic catalysis; Non-ionic surfactant; Dimyristoyl phosphatidic acid; Langmuir monolayers; Adsorption isotherm
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/S0927-7765(01)00302-2

The kinetics and the adsorption isotherms of the surfactant-solubilized alkaline phosphatase from rat osseous plate adsorbed by dip-coating on dimyristoyl phosphatidic acid (DMPA) Langmuir–Blodgett (LB) films were studied. The phosphomonohydrolase activity of the enzyme on the LB film was estimated by the hydrolysis of
p-nitrophenylphosphate (PNPP). Films prepared from solutions containing 0.30 μg ml
−1 of protein showed maximum activity for the supported enzyme above the critical micellar concentration of the non-ionic surfactant (polyoxyethylene-9-lauryl ether) used for enzyme solubilization. The surface density of the enzyme on DMPA LB films was determined from quartz crystal microbalance measurements. A consistent explanation concerning the maximum enzymatic activity is supported by data of surface tension for the mixed non-ionic surfactant–enzyme system.