The phosphorylation level of a particular protein can be determined using a procedure based upon western immunoblotting, with Phos-tag™ reagent present in the SDS-PAGE gel. The Phos-tag™ reagent, supplied in the form of Phos-tag™ acrylamide (Wako Pure Chemical Industries, AAL-107), causes proteins to be resolved both on the basis of size and phosphorylation state. This means that phosphorylated and de-phosphorylated forms of the same protein can be distinguished.
This protocol describes the transcriptional profiling of E. coli cultures using microarrays. The protocol utilises RNA isolated as described in another SOP (SUMO RNA isolation from E. coli) and with hybridisation to Ocimum Ocichip E. coli K-12 microarrays.