Updated project metadata. Labeling active ribosome associated proteins by L-Azidohomoalanine (AHA)- pulldown. Humane embryonic stem cells were labeled via AHA in methionine-free medium for 40 min. AHA labeled nascent proteins together with ribosomes and associated proteins were isolated with beads. Samples were divided into ribosome plus associated protein fraction and nascent protein fraction by 8M UREA wash.