Detection of glucose oxidase (GOX) and defensin-1 (Def-1) in honeydew honey samples (n = 23) and medical-grade manuka and kanuka honey following proteinase K treatment by immunoblotting. Aliquots (15 μl) of 50% (w/v) honey solution with or without proteinase K were resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 16.5% Tricine-SDS-PAGE. After semi-dry blotting procedure, the blocked membrane was incubated overnight with a rabbit polyclonal antibody against honeybee GOX or Def-1 (1:2000). Shown are cropped blots. (The blots with indicated cropping lines are shown in Supplementary Fig. S2). Immunoreactive bands were detected in solution containing dissolved SigmaFast 3,3-diaminobenzidine tablets (GOX) or detected using an enhanced chemiluminescence Immobilon Western kit (Def-1).