June 26th of 2000, a monumental work regarding to the mystery of life --- humanity genome sequence map had been first declared in Hilton hotel of Washington. This is the significant science and technological engineering next to Manhattan Project of Atomic Bomb and Apollo Project for to land on the moon. The accomplishment of the humanity genome sequence map, market the unprecedented depth and scope of the recognition of humanity to the biological phenomena, simultaneously proclaimed the arrival of a new era---post gene time . Proteome study becomes the strategic target of 21 century.
　　Gene is the fountainhead of the inherited information. Functional protein are the executive bodies of the gene information..
　　In order to understand the direct immediate molecule basis of varies biological phenomena, protein---the executive body of life activities must be the studying object. To launch an extensive, plenary points research into proteome expressing map of mankind organization or cellula are the developing direction in the present day. The primary structure of protein are the foundation for the proteome research.
　　All protein in all species, regardless of their function or biological activities, are build from the same set of twenty amino acids. But each protein has a specific chemical or structure function because of its distinctive number and sequence of amino acids residues and of its unique three dimensional structure. 　　Conceptually, protein structure can be considered at four levels:
　　Primary structure includes all the covalent bands between amino acid residues and is normally defined by the sequence of peptide-bonded amino acid residues and the locations of disulfide bonds.
Secondary structure refers to regular, recurring arrangements in space of adjacent amino acid residues in a polypeptide chain. There are a few common types of secondary structure, the most prominent being the helix and the conformation.
　　Tertiary structure refers to the spatial relationship among all amino acid residues in a polypeptide. It is a complete three-dimensional structure of a polypeptide. The boundary between secondary and tertiary structure is not always clear. But all of their structure are determined by its amino acid residues sequence.
　　Quaternary structure, which refers to the multiple noncovalent interactions between the subunits of oligomeric proteins or large protein assemblies. The association of polypeptide chains serve a variety functions..
　　Primary structure---the distinctive number and sequence of amino acid residues are the decisive factors to form all sorts of spatial structure of protein and ultimately its function.
　　Therefore, to determine the primary structure of protein--- the kind, the content, the proportion of component and the sequence of amino acid residues are the basis of deeply study and understanding to the relationship between molecular structures and biological functions.
　　The study of the primary structure of protein initiated from Prof. Frederick Sanger of Cambridge University in 1953. He makes use of his labeling reagent 2,4-dinitrofluorobenzene (DNFB),which undergoes nucleophilic substitution by the free amino group of protein to give an N-dinitrophenyl (DNP) derivative. The N-terminal residue, labeled by 2,4-dinitrophenyl group is separated and identified. After a series of hardships, Prof. Sanger achieved successes and reported the primary structure and the amino acid sequences of the polypeptide chains composing the protein insulin. Obviously, the synthesis of the new labeling reagent 2,4-dinitrofluorobenzene (DNFB) determined the outcome of the great achievement.
In order to reveal the secrets of the life, to place research and development of new type labeled reagent for the primary structure of protein on the new schedule just as a matter of course.When several new type labeled reagents can be found, can be chosen by the molecular biologists, it will be a new type assistant for protein study.
　　In history of science, several similar methodologies developed in the same period, a series of precedents can be found. Such as the determination of the precise order of nucleotide in a piece of DNA at high speed and efficiency. Two different techniques were developed almost simultaneously –the chain termination method by F.Sanger and A.R.Coulsion in the UK, and the the chemical degradation method by A.Maxam and W.Gilbert in USA. The two techniques are radically different but equally valuable . Both allow DNA sequence of several kilobase in length to be determined in the minimum time. For example, during 1980s, when the excitement engendered by the gene cloning revolution was at in its height, it hardly seemed possible that another, equally novel and equally revolutionary process was just around the corner. Kary Mullis invented the polymerase chain reaction (PCR) in 1985. His brainwave was an exquisitely simple technique that acts as a perfect complement to gene cloning. We can believe that the new type labeling reagent for the protein primary structure determination also will be a new excitement.
　　The new type labeling reagent for this research topic can be noted as following :
　　A.) The new labeling reagent can combine with the free amino terminus of a protein at moderate Conditions ;
　　B) The new type labeling reagent will be more safety ;
　　C) The new type labeling reagent can bring about new economic benefit ;
　　D) The achievement in the determination of the primary structure of protein can demonstrate an active influence on the subdivision of a discipline ; 　　
　　E) The achievement belongs to the fountainhead invention ;
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Li Shouchun
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Sino Italian Chemical Technology
　　　　　　　　　　　　　　　　　　　　　　　　　Research And Development Nanjing Institute April 14，2004