title: Purification and characterisation of multiple forms of polygalacturonase from mango (Mangifera indica cv. Dashehari) fruit.
abstract: Three multiple forms of polygalacturonase (PG) namely PGI, PGII and PGIII were isolated, purified and characterized from ripe mango (Mangifera indica cv. Dashehari) fruit. Native molecular weights of PGI, PGII and PGIII were found to be 120, 105 and 65kDa, respectively. On SDS-PAGE analysis, PGI was found to be a homodimer of subunit size 60kDa each while those of PGII and PGIII were found to be heterodimers of 70, 35 and 38, 27kDa subunit size each, respectively. Three isoforms of PG differed with respect to the effect of pH, metals, reducing agents and their susceptibility towards heat. PG isoforms also differed with respect to the effect of substrate concentration on enzyme activity. PGI and PGIII exhibited inhibition at high substrate concentration while PGII did not. Km for polygalacturonic acid was found to be 0.02% for PGI.
authors.affiliation: Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh 226 007, India.
authors.forename: Poorinima
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Biochemistry, University of Lucknow, Lucknow, Uttar Pradesh 226 007, India. Electronic address: upendradwivedi@hotmail.com.
authors.forename: Upendra N
authors.initials: UN
authors.lastname: Dwivedi
keywords: Dashehari; Mango; Multiple forms; Polygalacturonase; Polygalacturonic acid; Ripening