@article{1e25c8de2dc249d78ab3c310ef40b90d,
title = "Detection of platypus-type l/d-peptide isomerase activity in aqueous extracts of papaya fruit",
abstract = "Peptide isomerase catalyses the post-translational isomerisation of the l- to the d-form of an amino acid residue around the N/C-termini of substrate peptides. To date, some peptide isomerases have been found in a limited number of animal secretions and cells. We show here that papaya extracts have weak peptide isomerase activity. The activity was detected in each 30-100 kDa fraction of the flesh and the seed extracts of unripe and ripe papaya fruit. The definitive activity was confirmed in the ripe papaya extracts, but even then it was much less active than that of the other peptide isomerases previously reported. The activity was markedly inhibited by methanol, and partly so by amastatin and diethyl pyrocarbonate. This is the first report of peptide isomerase activity in a plant and suggests that perhaps every living organism may have some peptide isomerase activity.",
keywords = "Carica papaya L., Peptide isomerase, Peptidyl aminoacyl l/d-isomerase, d-Amino acid",
author = "Kensuke Arakawa and Koh, {Jennifer M.S.} and Ben Crossett and Torres, {Allan M.} and Kuchel, {Philip W.}",
note = "Funding Information: (dissolved in methanol) and diethyl pyrocarbonate (DEPC) were individually added to the reaction mixtures as peptide isomerase inhibitors. Methanol was used for a control of the inhibition assay using amastatin. P-Ctrl shows a positive control without heat treatment and without adding the inhibitors. All the chromatograms shown were recorded after 48 h of incubation Fellowships for Research Abroad. The mass spectrometry analyses were facilitated by access to the Sydney University Proteome Research Unit established under the Australian Government{\textquoteright}s Major National Research Facilities program and supported by the University of Sydney. Funding Information: Acknowledgments This work was funded by an ARC Discovery Project Grant to P. W. Kuchel and Professor J. I. Vandenberg. Dr. P. S. Bansal is thanked for vital earlier contributions to the work on platypus venom peptide isomerase. J. M. S. Koh was supported by an Australian Postgraduate Award. K. Arakawa was a recipient of a JSPS Postdoctoral",
year = "2012",
month = oct,
doi = "10.1007/s10529-012-0941-4",
language = "English",
volume = "34",
pages = "1659--1665",
journal = "Biotechnology Letters",
issn = "0141-5492",
publisher = "Springer Netherlands",
number = "9",
}