180-185Purification and characterization of an
extracellular invertase produced by Aspergillus ochraceus TS are reported.
The enzyme was purified (42-fold) from culture filtrate by salt precipitation,
ion-exchange and gel filtration. Sodium dodecyl
sulphate polyacrylamide gel electrophoresis
(SDS-PAGE) of the purified enzyme showed a single band of molecular mass 66
kDa. The molecular mass of the native enzyme was found to be 130 kDa by gel
filtration. The purity of the protein was
also checked against its antiserum raised in
rabbits by two-dimensional immunodiffusion in agarose gel and Western blot that
showed a single band. It is a glycoprotein with mannose as its carbohydrate
residue. The enzyme showed high affinity for sucrose with a Km of
3.5 <span style="font-size:14.0pt;font-family:Arial;
mso-fareast-font-family:" times="" new="" roman";mso-ansi-language:en-in;mso-fareast-language:="" en-in;mso-bidi-language:ar-sa"="" lang="EN-IN">mM. The amino acid analysis revealed a high proportion of
acidic residues but it had a low content of cysteine, histidine and arginine
comparable to other fungal invertases.</span