Bisubstrate analog

Bisubstrate analogs are compounds that contain features of both substrates for an enzymatic reaction in which two substrates are used. 

New derivatives of 4-amino and 2,4-diaminopteridines have been synthesized and their capability to inhibit neuronal nitric oxide synthase evaluated <99JMC4108>. The synthesis of folic acid multiply labeled with stable isotopes, for bioavailability studies in human nutrition, has been reported <99JCS(P1)1311>, Synthesis and antiviral evaluation of several 6-(methylenecarbomethoxy)pteridine-4,7-diones have been described <99JHC435>. Synthesis and biochemical evaluation of bis(6,7-dimethyl-8-D-ribityllumazines) as potential bisubstrate analog inhibitors of riboflavin synthase have been reported <99JOC4635>. Synthesis and cyclization of novel lumazine-enediyne chimeras have been reported <99H13>. 

Bone, R. Cheng, Y.C. Wolfenden, R. Inhibition of adenosine and thymidylate kinases by bisubstrate analogs. J. Biol. Chem., 261, 16410-16413 (1986)... 

Figure 29-13 (A) Structure of expected intermediate with tetrahedral C-atom in peptidyltransferase reaction with a tRNA, with a minihelix analog, or with the antibiotic puromycin. (B) Transition-state (or bisubstrate) analog formed with puromycin and a mimic of the CCA end of a tRNA. See Box 29-B.

Palcic MM, Heerze LD, Srivastava OP, Hindsgaul O. A bisubstrate analog inhibitor for a (l- 2.-fucosyltransferase. J. Biol. Chem. 1989 264 17174-17181. 

Figure 10.6. PALA, a Bisubstrate Analog. (Top) Nucleophilic attack by the amino group of aspartate on the carbonyl carbon atom of carbamoyl phosphate generates an intermediate on the pathway to the formation of N-carbamoylaspartate. (Bottom) A-(Phosphonacetyl)-l-aspartate (PALA) is an analog of the reaction intermediate and a potent competitive inhibitor of aspartate transcarbamoylase.

Paradoxical at first glance. Recall that phosphonacetyl-l-aspartate (PALA) is a potent inhibitor of ATCase because it mimics the two physiological substrates. However, low concentrations of this unreactive bisubstrate analog increase the reaction velocity. On the addition of PALA, the reaction rate increases until an average of three molecules of PALA are bound per molecule of enzyme. This maximal velocity is 17-fold as great as it is in the absence of PALA. The reaction rate then decreases to nearly zero on the addition of three more molecules of PALA per molecule of enzyme. Why do low concentrations of PALA activate ATCase ... 

J.A. Endrizzi, P.T. Beemink, T. Alber, and H.K. Schachman. 2000. Binding of bisubstrate analog promotes large structural changes in the unregulated catalytic trimer of aspartate transcarbamoylase Implications for allosteric regulation Proc. Natl. Acad. Sci. U. S. A. 97 5077-5082. (PubMed) (Full Text in PMC)... 

J.O. Newell, D.W. Markby, and H.K. Schachman. 1989. Cooperative binding of the bisubstrate analog A-(phosphonacetyl)-l-aspartate to aspartate transcarbamoylase and the heterotropic effects of ATP and CTP J. Biol. Chem. 264 2476-2481. (PubMed)... 

Parang, K., Cole, P. A. Designing bisubstrate analog inhibitors for protein kinases. Pharmacol. Then 2002, 3, 145—157. 

Figure 7. Interactions at the active site of aspartate transcarbamylase (ATCase). N-phosphonoacetyl-L-asparate (PALA) is a bisubstrate analog of the two natural substrates of ATCase, carbamyl phosphate and L-aspartate. PALA is shown bound in the active site of ATCase. Noncovalent interactions between PALA and side-chains of the protein are shown as dashed lines. Specific residues are indicated by their one letter abbreviation and by their position in the protein sequence (e.g., HI 34 = histidine at position 134). The active site is composed of residues from two separate polypeptide chains (denoted by primed and unprimed residue numbers). Note the complimentarity of the site and the ligand. The same interactions are used to align and catalyze the condensation of ATCase s natural substrates (Monaco et al., 1978).

Fig. 7.2-11 Cocrystal structure of bisubstrate analog 2 bound to the insulin receptor kinase (IRK) domain [41], IRK is shown in molecular surface representation with atoms of the N-terminal lobe colored blue and atoms of the C-terminal lobe colored gray. The molecular surface is semitransparent and shows the ATP moiety...

Fig. 7.2-12 Bisubstrate analog inhibitors of the insulin receptor kinase with varying linkers.

Bisubstrate Analog Designed for a Serine/Threonine Kinase... 

The favorable results in the case of the insulin receptor tyrosine kinase prompted the application of the bisubstrate analog approach to a serine/ threonine kinase [44]. Protein kinase A was selected because it had been... 

---