Isolation and purification of cysteine peptidases from the latex of Araujia hortorum fruits

Consistency of Polyphenol Oxidase (PPO) Thermostability in Ripening Apricots (Prunus armeniaca L.): Evidence for the Presence of Thermostable PPO Forming and Destabilizing Mechanisms in Apricots

“…Thus, the possible mechanism of TS-PPO formation and destabilization may simply be explained by the action of specific proteases that cause the modification of enzyme during ripening. In the literature the presence of at least five catalytic types of proteases was reported in plant tissues (39). It was found that some proteases cause only the modification of PPO, whereas some others cause a partial digestion of the enzyme and reduce its molecular weight (40).…”

A Highly Stable Biocatalyst Obtained from Covalent Immobilization of a Non-Commercial Cysteine Phytoprotease

“…The total protein content of araujiain was 5.4 mg protein/mL and the specific activity was 12.8 Ucas/ mg protein (68.4 Ucas/mL araujiain) when casein was used as substrate. Previous studies of Priolo and Obregón [9] reveal the presence of three fractions with proteolytic activity contained in this enzymatic extract [26,28]. Such fractions (called araujiain hI, hII and hIII) have synergistic activity and show better performance at different pH and temperatures in the proteolytic extract that when each working alone and isolated.…”

“…The supernatant was then ultracentrifuged (100,000 × g (60 min at 4°C)) and this new supernatant, called araujiain, was fractionated and conserved at -20°C for further studies. Cation exchange chromatography of araujiain reveals the presence of three fractions with proteolytic activity, according to previously described studies by Priolo and Obregón [26,28]. The protein content was estimated according to Bradford's assay using BSA as standard [31].…”

“…The general conditions for the immobilization of araujiain on glyoxyl-agarose were selected in function of i) the immobilization of other enzymes on glyoxyl-agarose; ii) previous knowledge on the preparation and characterization of the proteolytic extract from A. hortorum (Asclepiadaceae) fruit latex, and iii) the non-deactivating conditions for the proteases present in the enzymatic extract: the use of high pH values does not affect the performance of araujiain [13,26,28,36]. Since biocatalysts are designed to perform their activities in aqueous medium and in organic media, the pH value is important, since it is well established that enzymes "remember" the pH of the last aqueous solution in which they were dissolved and, after water removal, their ionization state remains unchanged (i.e., the optimum to display its maximum activity) [37].…”

“…This enzymatic preparation consisting on three papain-like cysteine peptidases was obtained from the latex of Araujia hortorum fruits (a climbing plant that grows in Brazil, Paraguay, Uruguay and Argentina) [26][27][28]. Araujiain has been demonstrated to be a successful biocatalyst for the synthesis of amide bonds in aqueous-organic media [9].…”