Unique Inhibitory Action of the Synthetic Compound 2-[N-(2-Aminoethyl)-N-(5-isoquinolinesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine (CKA-1306) against Calcium/Calmodulin-dependent Protein Kinase I
摘要:
A newly synthesized compound, 2-[N-(2-aminoethyl)-N-(5-isoquinolinesulfonyl)]amino-N-(4- chlorocinnamyl)-N-methylbenzylamine (CKA-1306), was found to inhibit cyclic AMP dependent protein kinase (PKA) and Ca2+/calmodulin-dependent protein kinase I (CaMK I) with IC50 values of 1.6 +/- 0.14 and 2.5 +/- 0.16 mu M, respectively. In contrast, the established PKA inhibitors H-8 and H-89 inhibited CaMK I with relatively high IC50 values of >100 and 24.4 +/- 3.2 mu M, respectively. An additional inhibitor, KN-62, against Ca2+/calmodulin-dependent protein kinase II (CaMK II) did not inhibit either PKA or CaMK I at the concentrations tested. In our library of many isoquinolinesulfonamide derivatives, only CKA-1306 inhibited CaMK I to a satisfactory degree, suggesting a unique mode of action. Indeed, the inhibition of CaMK I by CKA-1306 was competitive in every respect to Mg2+/ATP, peptide substrate (syntide-2), and Ca2+/calmodulin. This phenomenon may be understood from the context of the recently determined structure of the enzyme in its autoinhibited state Such kinetic analysis was also extended to cases using a phosphorylated and activated enzyme at Thr177 or a constitutively active, COOH-terminal truncated mutant at Gln293. CKA-1306 still competed with Mg2+/ATP for the two enzymes, but it no longer achieved any competitive advantage over syntide-2. These results may reflect some differences in the active conformation of CaMK I. However, the compound should be constant in its recognition of an Mg2+/ATP-binding site of the enzyme. Though CKA-1306 is not specific to CaMK I, the compound will be useful in studying the enzyme further under limited conditions. BIOCHEM PHARMACOL 56;3:329-334, 1998. (C) 1998 Elsevier Science Inc.
Convenient synthetic routes to KN-93, N-(2-[[(2E)-3-(4-chlorophenyl)prop-2-enyl](methyl)amino]methyl}phenyl)-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide, a well-known Ca²+/calmoduline-dependent protein kinase II (CaMKII) inhibitor, are described. The methods proposed start from easily available reagents and allow ready preparation of the final compound in moderate overall yields. Most of the