Protein kinase Activation by cAMP

Variability in hormonal response patterns does not stop at the level of second-messenger synthesis. Thus, cyclic AMP can activate the well-known cAMP-dependent protein kinase A, but the possibility of other cAMP-respon-sive enzymes or cAMP-activated regulatory proteins should not be ruled out. The protein kinase activated by cAMP can activate a number of other enzymes. For example, in the liver, phosphorylase kinase (see fig. 24.15) is activated and catalyzes the breakdown of glycogen. In adipocytes, triacyl-glycerol lipase is activated and catalyzes the breakdown of triacylglycerols. 

The method of protein kinase activation by cAMP is fairly well established but, more recently, information has emerged suggesting that at least in bacterial cells, the nucleotide also has a direct role in regulating the transcription process. It is thought to do this by binding to the DNA at the promoter site, complexed with a... 

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