"Electrophoretical Analysis of Casein Hydrolysates Produced by Plant Endopeptidases"

BRUNO, MARIELA A., PARDO, MARCELO F., TREJO, SEBASTIÁN A., SEQUEIROS, CYNTHIA, LÓPEZ, LAURA M. I., CAFFINI, NÉSTOR O. AND NATALUCCI, CLAUDIA L.

Córdoba, Argentina.

Congreso; XXXVII Reunión Anual de SAIB; 2001

SAIB

Objetives. Enzymatic hydrolysis of proteins alows to eliminate unwanted fractions or to modify functional properties. Four cysteine plant endopeptidases with basic optima pH isolated by us were used to partially hydrolyzed bovine casein and their peptide patterns are reported. Materials and methods. Plant proteases were isolated from latex of Asclepias fruticosa (I) and Philibertia gilliesii (II), and from fruits of Bromelia balansae (III) and Bromelia hieronymi (IV). Hydrolysis was carried out at 45 ºC and pH 8.0 with an enzyme/substrate relationship of 4.5 Ucas/g of casein. Hydrolysates were subjected to denaturing eletrophoresis in Tricine gels composed of a stacking gel (4%), a separating gel (10%) and a resolution gel (16,5%T), which is especially suitable to resolve the mixture of peptides produced. The electrophoretic profiles were analyzed by densitography. Results and Conclusions. Characteristic and differential proteolytic patterns on the main casein components (alfas 1, alfas 2, and beta fractions) were obtained for each protease. After ten minutes maximum degradation rate is observed for alfas2 and beta (I), alfas1 (II), alfas2 (III), and alfas1 and alfas2 (IV). New peptidases appeared; 20 kDa  (in II and IV), 13 kDa (in all hydrolysates), and < 10 kDa peptides characteristics for each hydrolysate. The patterns can be correlated with the modification of functional properties and the production of bitter peptides.