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Purification and characterisation of soluble acid invertase from mango fruits
Author(s) -
Li Renjie,
Li Jingyu,
Liao Xiaojun,
Wang Yongtao
Publication year - 2017
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.13354
Subject(s) - chemistry , invertase , mangifera , tryptophan , substrate (aquarium) , chromatography , sucrose , ammonium , analytical chemistry (journal) , enzyme , ion chromatography , circular dichroism , crystallography , amino acid , biochemistry , botany , biology , organic chemistry , ecology
Soluble acid invertase ( SAI ) was purified from mango fruits ( Mangifera indica L.) by ammonium sulphate fractionation and anion‐exchange chromatography ( DEAE ‐Sepharose Fast Flow). Molecular mass of the enzyme is 45 kDa estimated by SDS – PAGE . Dynamic light scattering analysis suggests the hydrodynamic radius of SAI distributes from 4 to 20 nm with a peak at 6.68 nm. Transmission electron microscopy shows that SAI is a globulin with diameter of 10–30 nm. Its optimal pH and temperature are 4.0 and 60 °C, respectively. The enzyme is not stable at high temperature (≥60 °C) or in alkaline ( pH ≥ 8) environment. Using sucrose as substrate, its K M and V max are 25.55 m m and 1.002 mmol min −1 mL −1 , respectively. Its circular dichroism spectrum shows a negative band at 220 nm and a positive band at 195 nm, suggesting a β‐sheet structure. The fluorescence spectra reflect that the tryptophan and tyrosine residues of SAI are partially exposed.