Binding characteristics of bovine serum albumin encapsulated in sol-gel glasses: an alternative for protein interaction studies.
Silica glasses doped with 500-700 microg of bovine serum albumin were prepared by the sol-gel method; two pH conditions (pH 5 and 7) were assayed for protein encapsulation. Both biomaterials showed a highly porous structure, with pore sizes in the range 5-28 nm. Columns packed with the ground biogels were on-line coupled to a C18 HPLC column for evaluation of the entrapped protein binding properties using propranolol. Binding capacities (at saturation) were approximately 3.7 and 7.1 microg of propranolol (drug-protein molar ratios 1.4 and 2.7) for the biogels prepared at pH 5 and 7, respectively. The significant difference indicates increased albumin denaturation upon encapsulation at pH 5. A frontal analysis study was then performed in cartridges packed with biogel prepared at pH 7 to evaluate the protein interaction with naproxen at low concentrations (<or=2 microg/ml). Up to 6.2 microg of naproxen was bound; the estimated n(eff)K(ass) (functional binding sites per albumin moleculexassociation constant) was 4 x 10(5)M(-1). Results corroborate the excellent preservation of native protein in sol-gel matrices, which, with low cost, simple preparation, and repeatable batch to batch characteristics, make these biomaterials an interesting alternative for studying solute-protein interactions.
Vera-Avila
Luz E
LE
Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, 04510 México D.F., Mexico. luzelena@servidor.unam.mx
García-Salgado
Erika
E
García de Llasera
Martha P
MP
Peña-Alvarez
Araceli
A
D000818:Animals; D002417:Cattle; D005782:Gels; D005898:Glass; D009288:Naproxen / Q000737:chemistry*; D011433:Propranolol / Q000737:chemistry*; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry*
D005782:Gels; D012710:Serum Albumin, Bovine; D009288:Naproxen; D011433:Propranolol