Recombinant DNA technology

While numerous proteins have been sequenced through Edman degradation and mass   spectrometry the determination of the complete   sequences   of large proteins through these techniques is a demanding and time-consuming procedure. Recombinant  DNA technology has enabled the sequences of even very large proteins or of proteins which are hard to purify to be determined  via ?rst  sequencing  the stretch  of DNA  encoding  the protein  and  then  using  the genetic  code  to decipher  the protein  sequence.  Even  so, some direct  protein  sequence   data  is  frequently  needed   to  con?rm   that  the  protein sequence obtained is the correct one and to identify any post-translational modi?cations  on the protein.  Therefore, DNA sequencing and protein sequencing methods are frequently used together to determine the complete sequence of a protein.