Acción de las peptidasas de Silybum marianum (L.) Gaertn sobre caseínas bovinas

Abstract

Las caseinas (CN) constituyen el 80% de las proteinas totales de la leche, siendo alfas1, alfas2, beta y kappa las cuatro fracciones mayoritarias. La función principal de las CN es nutritiva y los peptidos derivados de las mismas tienen interesantes aplicaciones como suplementos dietarios y en preparaciones farmaceuticas. Las CN totales fueron obtenidas a partir de leche bovina comercial por precipitacion isoeletrica y purificadas mediante cromatografia de intercambio anionico (FPLC) utilizando DEAE-Sepharose FF a pH 7,0. Las fracciones alfa y beta CN purificadas fueron hidrolizadas empleando aspartilendopeptidasas de flores de Silybum marianum y con cuajo bovino comercial. Tanto las CN como los peptidos obtenidos fueron analizados por electroforesis SDS Tricina PAGE y densitograma. Los perfiles hidroliticos mostraron una actividad diferencial y especifica con la preparacion enzimatica de S. marianum, sin proteolisis excesiva. En base a estos resultados, esta preparacion enzimatica podria ser empleada para la obtencion de nutraceuticos o como sustituto de rennet comercial.

Bovine milk contains four main types of casein (CN), αs1, αs2, β, and κ, constituting 80% of total protein milk. The main function of CN is nutritious and peptides derived from them have interesting applications as dietary supplements and pharmaceutical preparations. In the present work whole CN were obtaining from commercial bovine milk by isoelectric precipitation and were subsequently purified by anion exchange chromatography (FPLC) with DEAE Sepharose FF media, pH 7.0. α and β CN fractions purified were hydrolysed with aspartylendopeptidases from flowers of Silybum marianum and with commercial rennet. Both the CN as the peptides obtained were analyzed by electrophoresis (Tricine SDS PAGE) and densitograms. Hydrolytic profiles showed a differential and specific activity for the S. marianum enzymatic preparation without excessive proteolysis. Based on these results the enzymatic preparation could be advantageously for obtaining nutraceuticals or as a substitute for commercial rennet.