Multiple forms of β‐galactosidase from mango (Mangifera indica L Alphonso) fruit pulp

Abstract

Mango (Mangifera indica L cv Alphonso) was found to contain three isoforms (I, II and III) of β-galactosidase which, upon purification on Sephadex G-200, had relative abundances of 44, 38 and 18%, respectively. The total specific activity increased from 20 to 727 µmol l −1 upon purification, representing a ∼36-fold increase with a recovery of 0.28 U U −1 . The optimal pH for activity and stability were in the ranges 3.6-4.3 and 4-6.2, respectively. The optimal temperature for β-galactosidase activity was between 42 and 47 • C with T m in the range 45-51 • C. The K m for pNP-β-galactopyranoside was 0.98, 1.11 and 0.95 mM, and V max was 0.56, 0.53 and 0.35 µmol pNP min −1 , respectively for isoforms I, II and III. Hg 2+ caused strong inhibition, whereas galacturonic acid, galactose, xylose, fucose and mannose slightly inhibited the activity of β-galactosidase isoforms. The apparent molecular weights by GPC were 78, 58 and 91 kDa for isoforms I, II and III, respectively. The ability of these isoforms to degrade the endogenous substrate (arabinogalactan) possibly suggests a role in pectin dissolution during tissue softening/fruit ripening.

Transcriptional analysis of cell wall and cuticle related genes during fruit development of two sweet cherry cultivars with contrasting levels of cracking tolerance

“…Regarding β-Gal, this enzyme is most active in the later stages of fruit ripening as it has been reported in tomato (Smith et al, 2002), apple (Peña and Carpita, 2004), peach (Lee et al, 2003), and mango (Prasanna et al, 2005). However, in sour cherry Kovács et al (2008) showed that the maximum β-Gal activity occurs in the early stages of active growth and then decreases abruptly during fruit ripening, which agrees with the transcriptional profiles of β-Gal shown in our study ( Figure 3B).…”

β-Galactosidase from Ginkgo biloba seeds active against β-galactose-containing N-glycans: purification and characterization

“…Thus, β-Gal'ase Gb-1 may reside in the acidic region of plant cells, either in the cell wall or in vacuoles. β-Gal'ases isolated from other plant sources, such as carambola fruit, 18) mung bean, 38) mango fruit, 20) and kidney bean, 39) were also reported to be optimally active a Enzyme activity was determined using pNP-β-D-galactopyranoside. One unit of enzyme activity was defined as the amount of enzyme releasing 1 μmol of p-nitrophenol per min at 37°C.…”

“…From the view point of turnover mechanisms of the cell wall associated with plant differentiation or fruit ripening, many plant β-Gal'ases involved in the degradation of cell wall polysaccharide components from many types of plant materials (tomato, 5,9,10) carambola, 16) chick-pea, 17) Japanese pear, 18) pepper, 19) mango, 20) rice, 21) A. thaliana, 22) strawberry, 23) and orange 24) ) have been characterized, and their genetic identifications have been reported.…”

Mango

“…There is a rapid increase in water soluble pectin (WSP), chelator-soluble polyuronides, chelator soluble carbohydrates and a decrease in total polyuronides in mango during ripening (Ali et al 2004;Chaurasia et al 2006). The cell wall hydrolases implicated in pectin depolymerization in mango are polygalacturonases (PG), pectinesterases (PE), β-1,4-glucanases, β-galactosidases, galactanases, arabinanases and pectin lyases (PL) (Abu-Sarra & Abu-Goukh 1992; Ali et al 1995;Ashraf et al 1981;Chaurasia et al 2006;Mitcham & McDonald 1992;Prasanna et al 2003Prasanna et al , 2005Roe & Bruemmer 1981). PG can exist in two forms either as exo-PG or endo-PG.…”

“…Cellulases also show enhanced activities during ripening (Abu-Sarra & Abu-Goukh 1992;El-Zoghbi 1994;Lazan et al 1986;Prasanna et al 2003;Roe & Bruemmer 1981). The role of other hydrolases such as β-galactosidases, galactanases, arabinanases (Ali et al 2004;Lazan & Ali 1993;Prasanna et al 2003Prasanna et al , 2005 in mango fruit softening has also been observed. The activity of β-galactosidase increases seven fold during ripening of mango (Ali et al 2004).…”