Effects of neurotransmitters on cAMP-mediated signal transduction in frog olfactory receptor cells (ORCs) were studied using in situ spike recordings and radioimmunoassays. Carbachol, applied to the mucosal side of olfactory epithelium, amplified the electrical response of ORCs to cAMP-generating odorants, but did not affect unstimulated cells. A similar augmentation of odorant response was obs...

ABC transporters are remarkably versatile machines that move a wide array of substances, including both hydrophilic and hydrophobic molecules across membranes (1-4). They are constructed with a modular design; each transporter has two nucleotidebinding domains (NBDs) and two membrane-spanning domains (often comprising six transmembrane helices). The NBDs are highly conserved modules that intera...

Creatine kinase (EC 2.7.3.2) B-subunit activity in serum may be routinely measured as residual activity after specific immunoinhibition of the M-subunit. We assessed the inhibition kinetics, specificity, completeness of inhibition, and inhibitory capacity of three different anti-M preparations, with use of isolated human BB, MM, and MB isoenzymes. The Scandinavian-recommended reaction system wa...

The topological location of the nucleotide substrate binding environments on adenylate kinase has been explored with the fluorescent molecule [4-benzoyl]benzoyl-1-amidofluorescein (BzAF) and the nucleotide analog 3’-0-[4-benzoyl]benzoyl-ATP (BzATP), which a re site-directed photoaffinity probes that bind covalently at the individual nucleotide sites. The MgBzATP substituted for MgATP as a subs...

Activation of cAMP-dependent protein kinase II by static and dynamic steady-state cAMP levels was studied by reconstituting an in vitro model system composed of hormone-sensitive adenylate cyclase, cyclic nucleotide phosphodiesterase, and cAMP-dependent protein kinase II. The rates of cAMP synthesis were regulated by incubating isolated membranes from AtT20 cells with various concentrations of ...