Proteins from hand- and bee-collected pollen were isolated and separated in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional gel electrophoresis (2DE) system as well as by direct gel-free mass spectrometry (MS) analysis. Total thirty-six plant proteins with known functions and three uncharacterized were identified using mass spectrometry (MS) techniques from fourteen protein spots separated in 2D gel electrophoresis. Our study revealed two forms of profilin proteins with slightly different mass of 14.19 kDa and 14.09 kDa and beta actin fragment with 33.25 kDa both in hand- and bee-collected pollen as well proteins of thioredoxin family with molecular weight of 47.29 kDa. The antioxidant enzyme glucose oxidase (GOX) activity was investigated in twelve samples of monofloral willow honey, having Salix spp. pollen from 44.7 % to 80.2 %. Data of paired regression analysis between Salix spp. pollen content and GOX activity show moderate and negative correlation coefficient (r = - 0.56).

Keywords: willow pollen; honey; protein expression; separation; two-dimensional electrophoresis; mass spectrometry