Abstract: The reversible phosphorylation/dephosphorylation of protein is probably the most common andimportant regulatory modification of proteins.Synthesis and identification of phosphopeptide have beenshown to have dramatic agonist effects in several signaling pathways.The phosphoangiotensin Iwas syn-thesized with two different strategies: global approach and building block approach.The building block ap-proach using phosphorylation regeants di-tert-butyl-N,N-diethyl phosphoramidite is the preferred methodfor the synthesis of peptides containing phosphotyrosine.The phosphoangiotensin and angiotensin were easily distinguished by ESI-MS.It may be useful to determining the phosphrylation sites of peptidescontaining multi-phosphorylated tyrosines by multi-stage mass.The phosphorylation of angiotensin Ide-creases the content of-helix and increases the contents of -turn.

Key words: Phosphoangiotensin Ⅱ, Global approach, Building block approach, ESI-MS, CD spectra