Koshland

This concerted model assumes furthermore that the symmetry of the molecule is conserved so that the activity of all its subunits is either equally low or equally high, that is, all structural changes are concerted. Subsequently Daniel Koshland, University of California, Berkeley, postulated a sequential model in which each subunit is allowed independently to change its tertiary structure on substrate binding. In this model tertiary structural changes in the subunit with bound ligand alter the interactions of this... 

An Alternative Allosteric Model The Sequential Allosteric Model of Koshland, Nemethy, and Filmer... 

Koshland, D. E., Jr., Nemethy, G., and Filmer, D., 1966. Compari.son of experimental binding data and dieoretical models in proteins containing snbnnits. Biochemistry 5 365-385. The KNF model. 

FIGURE 7.1 Enzyme ortho- and allosterism as presented by Koshland [2], Steric hindrance whereby the competing molecules physically interfered with each other as they bound to the substrate site was differentiated from a direct interaction where only portions of the competing molecules interfered with each other. If no direct physical interaction between the molecules occurred, then the effects were solely due to effects transmitted through the protein structure (allosteric). 

Kaumann and Marano method, 267 Kinetic binding, 67 Koshland s hypothesis, 127-128... 

Figure 7-5. Two-dimensional representation of Koshland s induced fit model of the active site of a lyase. Binding of the substrate A—B induces conformational changes In the enzyme that aligns catalytic residues which participate in catalysis and strains the bond between A and B, facilitating its cleavage.

One example of a reactive ortho-hydroxybenzyl derivatives is the Koshland reagent I (Fig. 11.1).11 13 Its hydrolysis half-life in water (pH 3.5 and 25 °C) is... 

Horton, H. R. Koshland, D. E. Jr. A highly reactive coloured reagent with selectivity for the tryptophan residue in proteins 2-hydroxy-5-nitrobenzyl bromide. J. Amer. Chem. Soc. 1965, 87, 1126-1132. 

Seeker, W.R. and Koshland, C.P., Eds, Incineration of Hazardous Waste 2 Toxic Combustion By-products, Gordon and Breach Science publishers, Yverdon, Switzerland, 1994. 

Guacci V, Koshland D, Strunnikov A 1997 A direct link between sister chromatid cohesion and chromosome condensation revealed through the analysis of MCD1 in S. cerevisiae. Cell... 

Koshland D, Hartwell LH 1987 The structure of sister minichromosome DNA before anaphase in Saccharomjces cerevisiae. Science 238 1713—1716 KumadaK, Nakamura T, Nagao K, Funabiki H, Nakagawa T, Yanagida M 1998 Cutl is loaded onto the spindle by binding to Cut2 and promotes anaphase spindle movement upon Cut2 proteolysis. Curr Biol 8 633—641... 

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