The aim of this monograph is to summarize the essential features which
characterize the behavior of regulatory systems. Firstly we discuss the
laws which govern ligand binding in thermodynamic terms. The basic
cooperative and allosteric phenomena are des- cribed in thermodynamic
terms without assuming any particular mo- del. Then the molecular models
developed by Monod, Wyman and Changeux and by Koshland, Nemethy and
Filmer are presented in detail. Special emphasis has been given to the
analysis of the Hill coefficient and its meaning both in thermodynamic
terms and in terms of the two allosteric models: the concerted model of
Monod, Wyman and Changeux and the sequential model of Koshland, Nemethy
and Filmer. Special types of cooperativities are dis- cussed in some
detail namely, cooperativity stemming from ligand- coupled protein
association or dissociation, negative cooperati- vity and
half-of-the-sites reactivity. A slightly extended space was devoted to
the discussion of negative cooperativity and half- of-the-sites
reactivity, since the existence of these phenomena and their possible
biological importance is less of a common knowledge than positive
cooperativity. This monograph does not attempt to be a review of
specific examples analyzed according to one model or another. Rather, an
attempt is made to provide the reader with the quantitative tools to
analyze any specific regulatory system. Last but not least, I would like
to thank Prof. F. W. Dahlquist from the Institute of Molecular Biology,
the University of Oregon (Eugene) and Prof. D. E. Koshland, Jr.