Insights into the hydrolytic activity of Asclepias fruticosa L. protease

TORRES, MARÍA J.; NATALUCCI, CLAUDIA; LÓPEZ, LAURA M. I.; TREJO, SEBASTIÁN A.

BIOTECHNOLOGY LETTERS

SPRINGER

Lugar: Berlin; Año: 2019 vol. 41 p. 1043 - 1050

0141-5492

OBJECTIVE: To determine the enzymatic properties of asclepain f, a plant cysteine protease isolated and purified from the latex of Asclepias fruticosa, and to investigate its potential application to hydrolyze soybean proteins.RESULTS: Kinetic parameters were determined by hydrolysis of p-Glu-Phe-Leu-p-nitroanilide (PFLNA). The Km value for asclepain f was 6 to 8 times higher than those achieved for papain, bromelain and ficin, the main plant cysteine proteases. Asclepain f showed 12 cut-off points toward the oxidized B chain insulin, revealing that the enzyme possesses broad substrate specificity. The cut specificity was governed by the presence of hydrophobic residues (F, L, V) in the P2 position. Asclepain f was able to selectively hydrolyze soybean proteins at pH 10, employing an enzyme/substrate ratio of 0.2% (w/w). The enzymatic hydrolysis allowed a strong increase in the solubility, water and oil holding capacity.CONCLUSIONS: Asclepain f was revealed as a successful enzyme for biocatalysis of protein hydrolysis processes at alkaline pH. This new plant protease has a broad substrate specificity and is capable of selectively degrading the fractions of soy proteins and improving its functional properties.KEYWORDS: Asclepain f; Cysteine peptidase; Enzymatic hydrolysis; Cysteine peptidase; Cysteine peptidase; Specificity