Adenylyl cyclases: stimulation by hormones and regulation by nucleotides

摘要: Publisher Summary This chapter discusses the stimulation of adenylyl cyclases by hormones and regulation nucleotides. Most actions peptide protein hormones, those biogenic amines are result a primary interaction with membrane-bound receptor that initiates train events leading to activation nearby cyclase molecule formation second messenger, cAMP. The enzyme system is complex mode which occupied hormone stimulates its activity still unknown. None components hormone-sensitive system, be it receptor, catalytic unit, or coupling factor, has yet been purified homogeneity, not clear whether all them have even identified. As, one exception, solubilization systems resulted in loss hormonal responsiveness, their exploration extensively utilized indirect approaches. Indirect had take several factors into account: (1) effects seen may because alteration phospholipid matrix surrounding direct action on enzyme; (2) polymeric, being composed units; (3) kinetic modeling under both pre- post-steady-state conditions lend itself interpretations seldom mutually exclusive. In recent years, become increasingly nucleotides nucleosides. type modulation effected varies studied. Both positive negative observed either nucleoside triphosphates diphosphates.