Flux regulation

S Rossell, CC van der Weijden, A Lindenbergh, A van Tuijl, C Francke, BM Bakker, and HV Westerhoff, Unraveling the complexity of flux regulation A new method demonstrated for nutrient starvation in Saccharomyces cerevisiae. Proc. Natl. Acad. Sci. USA 103(7), 2166 2171 (2006). 

It quantifies the effect of a perturbation of an external effector A (e.g. the concentration of a nutrient) on the flux J via enzyme i. If A effects different enzymes, perturbations of A can effect J via different routes and the regulatory strengths quantify the relative importance of each of these regulatory routes. A different, but related approach was taken by Westerhoff and Ter Kuile (ter Kuile and Westerhoff 2001). They developed Regulation Analysis, a theory that quantifies the relative importance of flux regulation via metabolism and via gene expression (Section 2.5). 

S-lOOa (alpha-beta isoform) and S-lOOb (beta dimer). Each of the two subunits of this protein has a molecular weight approximating 10.5 kD, and the function of S-100 protein is essentially that of a calcium flux regulator. 

Dubinsky, Z. and Jokiel, P.L. (1994) Ratio of energy and nutrient fluxes regulates symbiosis between zooxanthellae and corals. Pacific Science, 48, 313—324. 

The outline of this chapter will follow a "system s approach" to regulation of smooth muscle relaxation and will be divided into sections dealing with ion flux regulation, key protein kinases, and regulation of cyclic nucleotides. For detail on the normal biochemi-cal/physiological function of these systems, the reader is referred to Chapters 9, 11, 12, 16, 20, and 22 in this volume. Where appropriate, differences between vascular, airway, gastrointestinal, and reproductive smooth muscle will be noted. 

---