Derivatization of phosphopeptides with mercapto- and amino-functionalized conjugate groups by phosphate elimination and subsequent Michael addition
作者:Kati Mattila、Jaana Siltainsuu、Lajos Balaspiri、Mikko Ora、Harri Lönnberg
DOI:10.1039/b505573c
日期:——
Kinetics of the β-elimination of the phosphate group from H–Tyr–Ser(PO3H2)–Phe–OH and H–Tyr–Thr(PO3H2)–Phe–OH and subsequent addition of thiols and amines to the dehydroalaninyl and β-methyldehydroalaninyl residues formed, were followed by RP HPLC under alkaline conditions in the absence and presence of Ba2+ ions. By this reaction sequence, the phosphoserinyl peptide was conjugated with mono-N-(2-mercaptoethyl)amide of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (4), a mercapto-functionalized pentapeptide, H–His–Gly–Gly–His–Gly–NH(CH2)4SH, and an amino-functionalized fluorescent dye, 5-dimethylaminonaphthalene-1-[N-(5-aminopentyl)]sulfonamide (dansyl cadaverine). The β-methyldehydroalanine residue was, in turn, observed to be a poor Michael acceptor.
在碱性条件下,在无 Ba2+ 离子和有 Ba2+ 离子存在的情况下,采用 RP HPLC 法对 H-Tyr-Ser(PO3H2)-Phe-OH 和 H-Tyr-Thr(PO3H2)-Phe-OH 中磷酸基团的β-消除以及随后硫醇和胺与脱氢丙氨酰和β-甲基脱氢丙氨酰残基的加成反应进行了动力学跟踪。通过这一反应序列,磷酸丝氨酰肽与 1,4,7,10- 四氮杂环十二烷-1,4,7,10-四乙酸的单-N-(2-巯基乙基)酰胺(4)(一种巯基官能化的五肽)共轭、H-His-Gly-Gly-His-Gly-NH(CH2)4SH,以及氨基官能化荧光染料--5-二甲基氨基萘-1-[N-(5-氨基戊基)]磺酰胺(丹参素)。据观察,β-甲基脱氢丙氨酸残基又是一种较差的迈克尔受体。