Purification and Characterization of Two Different -L-Rhamnosidases,RhaA and RhaB, from Aspergillus aculeatus

Two proteins exhibiting -L-rhamnosidase activity, RhaA and RhaB, were identified upon fractionation and purification of a culture filtrate from Aspergillus aculeatus grown on hesperidin. Both proteins were shown to be N glycosylated and had molecular masses of 92 and 85 kDa, of which approximately 24 and 15%, respectively, were contributed by carbohydrate. RhaA and RhaB, optimally active at pH 4.5 to 5, showed Km and Vmax values of 2.8 mM and 24 U/mg (RhaA) and 0.30 mM and 14 U/mg (RhaB) when tested for p-nitrophenyl--L-rhamnopyranoside. Both enzymes were able to hydrolyze -1,2 and -1,6 linkages to -D-glucosides. Using polyclonal antibodies, the corresponding cDNA of both -L-rhamnosidases, rhaA and rhaB, was cloned. On the basis of the amino acid sequences derived from the cDNA clones, both proteins are highly homologous (60% identity).

Bibliographic Details

Main Authors:	Manzanares, Paloma, van den Broeck, Hetty C., Graaff, Leo H. de, Visser, Jaap
Format:	artículo biblioteca
Language:	English
Published:	American Society for Microbiology 2001-05
Subjects:	Aspergillus aculeatus, Rhamnosidases,
Online Access:	http://hdl.handle.net/2431/73 http://hdl.handle.net/10261/3070
Tags:	Add Tag No Tags, Be the first to tag this record!