Purification and characterization of a thiol amylase over produced by a non-cereal non-leguminous plant, Tinospora cordifolia

A 43 kDa α-amylase was purified from Tinospora cordifolia by glycogen precipitation, ammonium sulfate precipitation, gel filtration chromatography, and HPGPLC. The enzyme was optimally active in pH 6.0 at 60 °C and had specific activity of 546.2 U/mg of protein. Activity was stable in the pH range of 4–7 and at temperatures up to 60 °C. PCMB, iodoacetic acid, iodoacetamide, DTNB, and heavy metal ions Hg2+ > Ag+ > Cd2+ inhibited enzyme activity while Ca2+ improved both activity and thermostability. The enzyme was a thiol amylase (3 SH group/mole) and DTNB inhibition of activity was released by cysteine. N-terminal sequence of the enzyme had poor similarity (12–24%) with those of plant and microbial amylases. The enzyme was equally active on soluble starch and amylopectin and released maltose as the major end product.

A thiol amylase, purified from an over producing non-cereal non-leguminous plant Tinospora cordifolia, had little N-terminal amino acid sequence similarity with those of plant and microbial amylases. The enzyme hydrolyzed both starch and amylopectin equally and showed better thermo and acid stabilities than commercial fungal amylase.Figure optionsDownload as PowerPoint slide