In frog photoreceptor membranes, light induces a dephosphorylation of two small proteins and a phosphorylation of rhodopsin. The level of phosphorylation of the two small proteins is influenced by cyclic GMP. Measurement of their phosphorylation as a function of cyclic GMP concentration shows fivefold stimulation as cyclic GMP is increased from 10(-5) to 10(-3) M. This includes the concentratio...

CO-free hydrogen is produced by the reversible cyclic stepwise steam reforming of methane for use in fuel cells and other processes that are sensitive to CO poisoning. The process consists of two steps involving the decomposition of methane in a first step followed by steam gasification of the surface carbon in a second step. The ease of carbon removal in step II is strongly dependent on temper...

CYCLIC NUCLEOTIDES mediate many aspects of normal cellular metabolism; thus, degradation as well as synthesis of these intracellular mediators must be strictly regulated. Phosphodiesterase (PDE), the enzyme of cyclic nucleotide catabolism, is present in mammalian tissues in multiple forms, which differ in substrate specificity, kinetic characteristics and sub-cellular localisation. Moreover, a ...