(n.) A process by which reaction occurs in the presence of certain agents which were formerly believed to exert an influence by mere contact. It is now believed that such reactions are attended with the formation of an intermediate compound or compounds, so that by alternate composition and decomposition the agent is apparenty left unchanged; as, the catalysis of making ether from alcohol by means of sulphuric acid; or catalysis in the action of soluble ferments (as diastase, or ptyalin) on starch.
(n.) The catalytic force.
Example Sentences:
(1) Nucleotide, which is essential for catalysis, greatly enhances the binding of IpOHA by the reductoisomerase, with NADPH (normally present during the enzyme's rearrangement step, i.e., conversion of a beta-keto acid into an alpha-keto acid, in either the forward or reverse physiological reactions) being more effective than NADP.
(2) The physiologically important metal ion for catalysis is Mg2+; however, Mn2+ supports in vitro activity, though at a reduced level.
(3) High intensity ultrasound also enhances the heterogeneous catalysis of alkene hydrogenation by Ni powders.
(4) We support the view that catalysis by metalloenzymes may be a reflection of the chemistry of the metal ion itself as a Lewis acid, and that perhaps too much emphasis has been placed on supposed special characteristics (such as strains, "entasis") of the enzyme-metal ion association.
(5) With copper-ion catalysis, ligands inhibit competitively.
(6) Clearly the cysteines play no essential role in catalysis or cyclosporin A binding.
(7) Some mechanisms that can provide catalysis of phosphoryl transfer through a metaphosphate-like transition state are reviewed briefly.
(8) To investigate the ability of a protein to accommodate potentially destabilizing amino acid substitutions, and also to investigate the steric requirements for catalysis, proline was substituted at different sites within the long alpha-helix that connects the amino-terminal and carboxyl-terminal domains of T4 lysozyme.
(9) The C-terminal domain (327 amino acids) is responsible for catalysis and binds the two zinc ions, which are 2.88 A apart.
(10) Determination of the rate of CO2 production permitted the calculation of capillary blood volume, mean capillary transit time, and the degree of catalysis of CO2 reactions by carbonic anhydrase present in the lung.
(11) The species invariance of this lysine residue, number 175, and the substantial conservation of adjacent sequence support the probability for a functional role in catalysis of the lysyl epsilon-amino group.
(12) Catalysis is processive at optimum salt concentration and distributive at a higher one; camptothecin decreases the initial rate of reaction in both salt conditions, but more so at the higher one.
(13) No evidence for the participation of the fully reduced flavoprotein in catalysis could be obtained.
(14) Additional studies reported here showed that acylation of PLA2 was not necessary for catalysis or binding to the interface and that the binding of the substrate to the active site of PLA2 was not necessary for the binding of the enzyme to the interface.
(15) The UTP concentration dependence for photolabeling was the same as that for promoting catalysis.
(16) The extent catalysis of phosphodiester bond formation varied with the particular clay mineral used.
(17) Comparison of the specific activities for aniline hydroxylation and p-nitrophenol hydroxylation of individual microsomal samples from control, ethanol-pretreated and phenobarbital-pretreated animals showed a high degree of correlation (r2 = 0.98) consistent with the involvement of the same site for catalysis of these two compounds.
(18) Limited data indicates that, while enhanced thermal stability invariably results, the optimum temperature for catalysis may not change.
(19) These results suggest that two convalent intermediates, phosphoryl and malonyl enzyme, are sequentially formed in the synthesis of malonyl-coenzyme A by malonyl-coenzyme A synthetase catalysis.
(20) During catalysis in the scooting mode the enzyme does not leave the surface of the vesicle to which it is bound.
Catalytic
Definition:
(a.) Relating to, or causing, catalysis.
(n.) An agent employed in catalysis, as platinum black, aluminium chloride, etc.
Example Sentences:
(1) Evidence is presented that the protein can act catalytically.
(2) Replacement of vinyl groups with bulkier substituents (hydroxyethyl or acetyl groups) decreases holoenzyme stability and catalytic activity.
(3) Azocoupling of the alkaline phosphatase with diazonium-1-H-tetrazole and Zn2+ content measurement of azocoupled enzyme probes indicated that 2 histidine residues per subunit are involved in binding of the catalytically important Zn2+.
(4) Deuterium-labeled aspirin (2-acetoxy[3,4,5,6-2H4]benzoic acid) was synthesized from salicylic acid by catalytic exchange and subsequent acetylation.
(5) Treatment with the endoglycosidase did not alter the catalytic activity or heat stability of the acid lipase.
(6) Considering those portions of the molecule that can be deleted without a loss of catalytic activity, one is left with a catalytic center of approximately 130 nucleotides that is solely responsible for the molecule's activity.
(7) The two more reactive residues were confirmed not be essential for the catalytic activity for the hydrolysis of maltodextrin and phenyl alpha-maltoside.
(8) In the presence of ATP-Mg2+, the enzymes were rapidly phosphorylated in vitro by the catalytic subunit of cyclic AMP (cAMP)-dependent protein kinase purified from snail muscle and also by the C subunit of protein kinase from bovine heart.
(9) A secondary effect of such a structural change was that D1 and D2, two proteins that form the catalytic core (reaction center) of PSII, were also destabilized.
(10) Binding of cAMP to the regulatory subunits induces the dissociation of the holoenzyme and releases the free and active catalytic subunits.
(11) These results, in addition to binding studies with the active site titrant N2-(5-dimethylaminonaphthalene-1-sulfonyl)arginine N-(3-ethyl-1,5-pentanediyl)amide, indicate that binding interactions at the catalytic site of Thrombin Quick I are unaltered.
(12) It dissociates in the presence of cAMP into a cAMP-binding protein, R2 (Mr 90,000) and a catalytic subunit C (Mr 33,000).
(13) The enzyme is immobilized to provide better control over its catalytic activity and to increase the lifetime of the biosensor.
(14) As a result of differences in pH optima for catalytic activity, lipoxygenases were selectively detected by adjusting the pH employed for activity-specific staining.
(15) Physical properties of the catalytic subunit were determined by several different methods.
(16) The catalytic activity of ribonucleic acid is reviewed, with the intervening sequence (IVS) of the ribosomal RNA precursor of Tetrahymena serving as a major example.
(17) In the catalytic domain PPV and PPX are more similar to PP2A (57-69% identity) than PP1 (45-49% identity), while PPY and PPZ are more similar to PP1 (66-68% identity) than PP2A (44% identity).
(18) In addition, the trends in the three sets of data for the catalytic subunit indicate that ionic bonds are involved in binding PALA to the active site, and that non-productive binding by L-Asp is negligible under these experimental conditions.
(19) The reaction of p-nitrophenyl 4-guanidinobenzoate (NPGB) with human serum albumin (HSA) was examined kinetically at various pH's and 25 degrees C. The Michaelis constant (Ks in M) and the catalytic rate constant (k2 in s-1) were determined.
(20) A model is proposed in which this region interacts with a catalytic core to maintain the I state, and in which phosphorylation serves to uncouple this interaction.