Use of electrospray mass spectrometry for mass determination of grape (Vitis vinifera) juice pathogenesis-related proteins: A potential tool for varietal differentiation
Y. Hayasaka et al., Use of electrospray mass spectrometry for mass determination of grape (Vitis vinifera) juice pathogenesis-related proteins: A potential tool for varietal differentiation, J AGR FOOD, 49(4), 2001, pp. 1830-1839
Methods based on liquid chromatography-mass spectrometry (LC-MS) and protei
n trap mass spectrometry (trap-MS) were developed to determine the compleme
nt of pathogenesis-related (PR) proteins in grape juice. Trap-MS was superi
or to LC-MS in terms of simplicity, rapidity, and sensitivity. Proteins wit
h a wide range of masses (13-33 kDa) were found in the juices of 19 differe
nt varieties of grape (Vitis vinifera) and were identified as mostly PR-5 t
ype (thaumatin-like) and PR-3 type (chitinases) proteins. Although the PR p
roteins in juices of grapes are highly conserved, small consistent differen
ces in molecular masses were noted when otherwise identical proteins were c
ompared from different varieties. These differences persisted through diffe
rent harvest years and in fruits grown in different Australian locations. W
ith the definition of four different masses for PR-5 proteins (range = 2123
9-21272 Dal and nine different masses of PR-3 proteins (range 25330-25631 D
al and using statistical analysis, the methods developed could be used for
varietal differentiation of grapes grown in several South Australian locati
ons on the basis of the PR protein composition of the juice. It remains to
be seen whether this technology can be extended to grapes grown worldwide a
nd to wine and other fruit-derived products to assist with label integrity
to the benefit of consumers.