Vinita Yadav

Publications (8) View all

• Article: In Silico characterization of glycosidase protein sequences from bacterial sources.

  Vinita Yadav, Kapil Deo Singh Yadav
  Online Journal of Bioinformatics. 06/2012; 13(1-1443-2250):156-166.
• Article: Purification and functional characterisation of an α-l-rhamnosidase from Penicillium citrinum MTCC-3565

  Sarita Yadav, Vinita Yadav, Sudha Yadava, Kapil D.S. Yadav
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  ABSTRACT: An extracellular α-l-rhamnosidase from Penicillium citrinum MTCC-3565 has purified to homogeneity from its culture filtrate using ethanol precipitation and cation-exchange chromatography on carboxymethyl cellulose. The purified enzyme gave a single protein band corresponding to molecular mass of 45.0 kDa in SDS-PAGE analysis showing the purity of the enzyme preparation. The native PAGE analysis showed the monomeric nature of the purified enzyme. Using p-nitrophenyl α-l-rhamnopyranoside as substrate, Km and Vmax values of the enzyme were 0.30 mm and 27.0 μm min mg−1, respectively. The kcat value was 20.1 s giving kcat/Km value of 67.0 mm s−1 for the same substrate. The pH and temperature optima of the enzyme were 8.5 and 50 °C, respectively. The activation energy for the thermal denaturation of the enzyme was 29.9 KJ mol−1. The α-l-rhamnosidase was able to hydrolyse naringin, rutin and hesperidin and liberated l-rhamnose, indicating that the purified enzyme can be used for the preparation of α-l-rhamnose and pharmaceutically important compounds by derhamnosylation of natural glycosides containing terminal α-l-rhamnose. The α-l-rhamnosidase was active at the level of ethanol concentration present in wine, indicating that it can be used for improving wine aroma.
  International Journal of Food Science & Technology 04/2012; 47(7-1365-2621):1404–1410. · 1.26 Impact Factor
• Article: Purification, characterisation and application of α-l-rhamnosidase from Penicillium citrinum MTCC-8897

  Sarita Yadav, Vinita Yadav, Sudha Yadav, Kapil D.S. Yadav
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  ABSTRACT: An α-l-rhamnosidase secreted by Penicillium citrinum MTCC-8897 has been purified to homogeneity from the culture filtrate of the fungal strain using ammonium sulphate precipitation and cation-exchange chromatography on carboxymethyl cellulose. The sodium dodecyl sulphate/polyacrylamide gel electrophoresis analysis of the purified enzyme gave a single protein band corresponding to the molecular mass 51.0 kDa. The native polyacrylamide gel electrophoresis also gave a single protein band confirming the enzyme purity. The Km and Vmax values of the enzyme for p-nitrophenyl α-l-rhamnopyranoside were 0.36 mm and 22.54 μmole min−1 mg−1, respectively, and kcat value was 17.1 s−1 giving kcat/Km value of 4.75 × 104 m−1 s−1. The pH and temperature optima of the enzyme were 7.0 and 60 °C, respectively. The purified enzyme liberated l-rhamnose from naringin, rutin, hesperidin and wine, indicating that it has biotechnological application potential for the preparation of l-rhamnose and other pharmaceutically important compounds from natural glycosides containing terminal α-l-rhamnose and also in the enhancement of wine aroma.
  International Journal of Food Science & Technology 11/2011; 47(2-1365-2621):290–298. · 1.26 Impact Factor
• Article: α‐l‐Rhamnosidase from Aspergillus flavus MTCC‐9606 isolated from lemon fruit peel

  Vinita Yadav, Sarita Yadav, Sudha Yadava, Kapil D.S. Yadav
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  ABSTRACT: An α-l-rhamnosidase producing fungal strain has been isolated from decaying lemon fruit. The fungal strain has been identified as Aspergillus flavus. The α-l-rhamnosidase has been purified from the culture filtrate of the fungal strain using ultra filtration and cation exchange chromatography on carboxy methyl (CM) cellulose. The molecular mass of the purified enzyme determined by SDS–PAGE analysis was 41 kDa. The Km values of the enzyme using p-nitrophenyl-α-l-rhamnopyranoside and naringin as the substrates were 1.89 and 1.6 mm respectively. The pH and temperature optima of the enzyme were 11.0 and 50 °C respectively. The effects of various chemical species present in grape fruit juice and wine on the activity of the enzyme have been determined.
  International Journal of Food Science & Technology 01/2011; 46(2):350 - 357. · 1.26 Impact Factor
• Article: In silico analysis of α-L-rhamnosidase protein sequences from different source organisms.

  Vinita Yadav, Dinesh Yadav, Kapil Deo Singh Yadav
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  ABSTRACT: A total of 64 protein sequences of α-L-rhamnosidase representing different source organisms available in GenBank were downloaded and in silico characterized for homology search, multiple sequence alignment, domain analysis and phylogenetic tree construction to reveal sequence level similarity. Two major clusters representing bacterial and fungal α-L-rhamnosidase were observed. The multiple accessions of different bacterial and fungal sources formed clusters revealing a sequence level similarity. The multiple sequence alignment of α-L-rhamnosidase protein sequences from different source organisms showed conserved regions at different stretches indicating homology at sequence level. A total of seven motifs were observed in MEME which showed similarity with Bacrhamnosid family belonging to clan six hairpin glycosidase hydrolases super family which is conserved in all the fungal and bacterial α-L-rhamnosidase protein sequences. One of the motifs showed similarity with Bac_rhamnoside_N domain belonging to clan galactose-binding domain-like superfamily. The presence of such motifs is indicative of its structural organization with six helical hairpins and β-sandwich domain involved in carbohydrate recognition.
  Online Journal of Bioinformatics. 01/2010; 11:293-301.