RESUMEN
Amygdalus pedunculata Pall is a kind of desert woody oil plant, and its seeds are high in protein. The protein of Amygdalus pedunculata Pall (API) was identified by SDS-PAGE, 2-DE and MS. More than 300 proteins were identified. The improved solubility, emulsifying properties and foaming properties of API were observed in a pH range of 2.0-12.0 and a sodium chloride concentration of 0-1.0 M. The results showed that API had a good solubility (94.2%), bulk density (0.107 g/mL), oil absorption capacity (3.54 g/g), thermal stability (91.58 °C), emulsifying property (70 m2/g) and foaming property (83.7%). The conformation changes of API were studied by fluorescence and differential scanning calorimetry (DSC). The degree of denaturation of denaturants for API was guanidine hydrochloride > urea > SDS. These results showed that API has good processing performance and can be used as a new type of plant protein resource.
Asunto(s)
Proteínas de Plantas/química , Prunus/metabolismo , Semillas/metabolismo , Rastreo Diferencial de Calorimetría , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Proteínas de Plantas/metabolismo , Desnaturalización Proteica , Estabilidad Proteica , Prunus/química , Semillas/química , Cloruro de Sodio/química , Solubilidad , TemperaturaRESUMEN
Hydroxynitrile lyases (HNLs) are widely used in the asymmetric synthesis of cyanohydrins which are organic compounds used in the production of fine chemicals and pharmaceuticals, because these enzymes exhibit high catalytic efficiency and are very economical. In the present study, seeds of A. pedunculata Pall were identified as new potential source of HNLs. The HNL from A. pedunculata Pall (APHNL) was purified 138 fold and 4.20% yield with a specific activity of 661â¯U/mg. SDS-PAGE result showed the enzyme to be present as a monomer and the relative molecular mass determined by MALDI-TOF MS was 61â¯kDa. APHNL owned highest activity at pHâ¯6.0 and at 60 °C temperature, showing activity up to 80⯰C and stable up to 60⯰C. APHNL has a Km of 0.5â¯mM, Vmax of 665.9⯵molâ¯mg-1â¯min-1, Kcat of 676.5â¯s-1 and Kcat/Km of 1353â¯s-1â¯mM-1 using mandelonitrile as substrate. Syntheses of (R)-mandelonitrile and (R)-2-Hydroxy-2-(3-phenoxy-phenyl)-acetonitrile were carried out using APHNL and molar conversion of (R)-mandelonitrile and (R)-2-Hydroxy-2-(3-phenoxy-phenyl)-acetonitrile were 90% and 98% with 94% and 93% ee, respectively. These results indicated that APHNL was an excellent biocatalyst and has very high potential for synthesis of enantiopure cyanohydrins.