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Aspartic protease from Aspergillus niger: Molecular characterization and interaction with pepstatin A.

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Relation http://ir.cftri.com/14627/
https://doi.org/10.1016/j.ijbiomac.2019.07.133 0141-8130/
 
Title Aspartic protease from Aspergillus niger: Molecular characterization and
interaction with pepstatin A.
 
Creator Kavya, P.
Sagar, K. Bhat
Sridevi Annapurna, Singh
Gopal, K. M.
Appu Rao, A. G.
 
Subject 04 Fungi
05 Enzymes
 
Description In the pursuit of industrial aspartic proteases, aspergillopepsin A-like endopeptidase from the fungi Aspergillus
niger, was identified and cultured by solid state fermentation. Conventional chromatographic techniques were
employed to purify the extracellular aspartic protease to apparent homogeneity. The enzyme was found to
have single polypeptide chain with a molecular mass of 50 ± 0.5 kDa. The optimum pH and temperature for
the purified aspartic protease was found to be 3.5 and 60 °C respectively. The enzyme was stable for 60 min at
50 °C. The purified enzyme had specific activity of 40,000 ± 1800 U/mg. The enzyme had 85% homology with
the reported aspergillopepsin A-like aspartic endopeptidase from Aspergillus niger CBS 513.88, based on tryptic
digestion and peptide analysis. Pepstatin A reversibly inhibited the enzyme with a Ki value of 0.045 μM. Based
on homology modeling and predicted secondary structure, it was inferred that the aspartic protease is rich in
β-structures, which was also confirmed by CD measurements. Interaction of pepstatin A with the enzyme did
not affect the conformation of the enzyme as evidenced by CD and fluorescence measurements. Degree of hydrolysis of commercial substrates indicated the order of cleaving ability of the enzyme to be hemoglobin N defatted
soya flour N gluten N gelatin N skim milk powder. The enzyme also improved the functional characteristics of
defatted soya flour. This aspartic protease was found to be an excellent candidate for genetic manipulation for
biotechnological application in food and feed industries, due to its high catalytic turn over number and
thermostability
 
Date 2019
 
Type Article
PeerReviewed
 
Format pdf
 
Language en
 
Identifier http://ir.cftri.com/14627/1/International%20Journal%20of%20Biological%20Macromolecules%20139%20%282019%29%20199%E2%80%93212.pdf
Kavya, P. and Sagar, K. Bhat and Sridevi Annapurna, Singh and Gopal, K. M. and Appu Rao, A. G. (2019) Aspartic protease from Aspergillus niger: Molecular characterization and interaction with pepstatin A. International Journal of Biological Macromolecules, 139. pp. 199-212. ISSN 0141-8130