Specific monitoring of Syk protein kinase activity by peptide substrates including constrained analogs of tyrosine.
The ability of Syk protein tyrosine kinase (PTK) to phosphorylate peptides, where tyrosine had been replaced by conformationally constrained analogs, has been exploited to develop highly selective substrates suitable for the specific monitoring of Syk activity. In particular we have synthesized a peptidomimetic, RRRAAEDDE(L-Htc)EEV (syktide), with the 3(S)-7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxyl acid residue (L-Htc) replaced for tyrosine, which is phosphorylated by Syk with remarkable efficiency (K(cat)=73 min(-1), K(m)=11 microM), while it is not affected to any appreciable extent by a number of PTKs tested so far. These properties make syktide the first choice substrate for the specific monitoring of Syk.
Dipartimento di Chimica Biologica and Centro di Studio delle Biomembrane del CNR, University of Padova, Viale G. Colombo 3, 35121, Padua, Italy.
Arianna
A
Donella-Deana
Paolo
P
Ruzza
Luca
L
Cesaro
Anna Maria
AM
Brunati
Andrea
A
Calderan
Gianfranco
G
Borin
Lorenzo A
LA
Pinna
D000818:Animals; D004792:Enzyme Precursors / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines / Q000737:chemistry; D007700:Kinetics; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D000072377:Syk Kinase; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry
D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D007546:Isoquinolines; D010455:Peptides; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606898:Syk protein, rat