Purification and characterisation of a protease (tamarillin) from tamarillo fruit

Type
Article

Authors
Li, Zhao
Scott, Ken
Hemar, Yacine
Zhang, Huoming
Otter, Don

KAUST Department
Proteomics and Protein Expression

Online Publication Date
2018-02-16

Print Publication Date
2018-08

Date
2018-02-16

Abstract
A protease from tamarillo fruit (Cyphomandra betacea Cav.) was purified by ammonium sulphate precipitation and diethylaminoethyl-Sepharose chromatography. Protease activity was determined on selected peak fractions using a casein substrate. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis showed that the peak with the highest protease activity consisted of one protein of molecular mass ca. 70 kDa. The protease showed optimal activity at pH 11 and 60°C. It was sensitive to phenylmethylsulphonyl fluoride while ethylenediaminetetraacetic acid and p-chloromercuribenzoic acid had little effect on its activity, indicating that this enzyme was a serine protease. Hg2+ strongly inhibited enzyme activity, possibly due to formation of mercaptide bonds with the thiol groups of the protease, suggesting that some cysteine residues may be located close to the active site. De novo sequencing strongly indicated that the protease was a subtilisin-like alkaline serine protease. The protease from tamarillo has been named 'tamarillin'.

Citation
Li Z, Scott K, Hemar Y, Zhang H, Otter D (2018) Purification and characterisation of a protease (tamarillin) from tamarillo fruit. Food Chemistry. Available: http://dx.doi.org/10.1016/j.foodchem.2018.02.091.

Acknowledgements
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Publisher
Elsevier BV

Journal
Food Chemistry

DOI
10.1016/j.foodchem.2018.02.091

Additional Links
http://www.sciencedirect.com/science/article/pii/S0308814618303273

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