SummaryMolecular catalysis of ATP-hydrolysis by a number of protonated macrocyclic polyamines 1-9 has been investigated by 31P-NMR spectroscopy, and marked rate enhancements have been obtained. The largest acceleration is produced by the [24]-N,O, macrocycle 1, and the process displays the following properties: 1. protonated 1 forms very stable complexes with ATP, as well as with ADP and AMP; 2. it enhances the rate of ATP-hydrolysis by a factor of lo3 at pH = 8.5; the rate of hydrolysis is constant over a wide pH-range, from pH = 2.5 to 8.5; 3. 1 is more efficient than acyclic analogues; 4 . the products of the reaction are orthophosphate (OP) and ADP, which is subsequently hydrolyzed to OP and AMP at a slower rate; 5. at pH > 6.5, a transient species is detected, which is tentatively identified as a phosphoramidate intermediate, resulting from phosphorylation of the macrocycle 1 ; 6. the reaction presents first-order kinetics and is catalytic. The mechanism of the process is discussed in terms of initial formation of a complex between ATP and protonated 1, followed by an intracomplex reaction which may involve a combination of nucleophilic or acid catalysis with electrostatic catalysis.Introduction. -Molecular catalysis represents a major feature of the functional properties of supramolecular systems [ 11. In particular, the recent development of anion receptor molecules ([2] [3] and references therein), organic ligands which bind organic and inorganic anions, opens the way to the design of molecular catalysts capable of effecting reactions on a bound anionic substrate.Complexation and transformation of substrates of biological importance are of special interest in this respect. Notably, formation and hydrolysis of adenosine-5'-triphosphate (ATP) occur via highly efficient enzymatic reactions catalyzed by the ATPases and play a key role in numerous biological processes : photosynthesis phosphorylation (chloroplast ATPase), oxidative phosphorylation (mitochondria1 ATPase), muscle action (myosin ATPase), active transport (Na, K-ATPase, Ca-ATPase) etc. There is therefore considerable interest in analyzing the controlling factors and the mechanism of

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Molecular recognition features the design of synthetic receptor molecules that have high affinity and specif-

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