The honey from chestnut, acacia, sunflower, eucalyptus and orange was analysed 
for its proteome content, in order to see if any plant proteins present would 
allow the proteo-typing of these different varieties. Since the total protein 
content turned out to be minute, 200g of each honey type were diluted to 1L and 
then added with ProteoMiner to enhance the visibility of the proteinaceous 
material. All bands visible in the SDS-PAGE profile of each type of honey were 
eluted, digested and identified by mass spectrometry in a LTQ-XL instrument. It 
turned out that all proteins identified (except one, the enzyme 
glyceraldehyde-3-phosphate dehydrogenase from Mesembryanthemum crystallinum) 
were not of plant origin but belonged to the Apis mellifera proteome. Among the 
total proteins identified (eight, but only seven as basic constituents of all 
types of honey) five belonged to the family of major royal jelly proteins 1-5, 
and were also the most abundant ones in any type of honey, together with 
α-glucosidase and defensin-1. It thus appears that honey has a proteome 
resembling the royal jelly proteome (but with considerably fewer species), 
except that its protein concentration is lower by three to four orders of 
magnitude as compared to royal jelly. Attempts at identifying additional plant 
(pollen, nectar) proteins via peptidome analysis were unsuccessful.