Mammalian l-to-d-amino-acid-residue isomerase from platypus venom.
The presence of d-amino-acid-containing polypeptides, defensin-like peptide (DLP)-2 and Ornithorhyncus venom C-type natriuretic peptide (OvCNP)b, in platypus venom suggested the existence of a mammalian d-amino-acid-residue isomerase(s) responsible for the modification of the all-l-amino acid precursors. We show here that this enzyme(s) is present in the venom gland extract and is responsible for the creation of DLP-2 from DLP-4 and OvCNPb from OvCNPa. The isomerisation reaction is freely reversible and under well defined laboratory conditions catalyses the interconversion of the DLPs to full equilibration. The isomerase is approximately 50-60 kDa and is inhibited by methanol and the peptidase inhibitor amastatin. This is the first known l-to-d-amino-acid-residue isomerase in a mammal.
School of Molecular and Microbial Biosciences, University of Sydney, Building G08, Sydney, NSW 2006, Australia.
Allan M
AM
Torres
Maria
M
Tsampazi
Chryssanthi
C
Tsampazi
Eleanor C
EC
Kennett
Katherine
K
Belov
Dominic P
DP
Geraghty
Paramjit S
PS
Bansal
Paul F
PF
Alewood
Philip W
PW
Kuchel
D000591:Amino Acid Isomerases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D000595:Amino Acid Sequence; D000818:Animals; D000432:Methanol / Q000494:pharmacology; D008969:Molecular Sequence Data; D010455:Peptides / Q000494:pharmacology; D010987:Platypus / Q000378:metabolism*; D014688:Venoms / Q000201:enzymology*
D010455:Peptides; D014688:Venoms; C016977:amastatin; D000591:Amino Acid Isomerases; D000432:Methanol