Purification and characterization of two different a-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␒dentity).
| Main Authors: | , , , |
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| Format: | Article/Letter to editor biblioteca |
| Language: | English |
| Subjects: | Life Science, |
| Online Access: | https://research.wur.nl/en/publications/purification-and-characterization-of-two-different-a-l-rhamnosida |
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| Summary: | 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␒dentity). |
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