Question

Protein phosphorylation to amino acid residues is commonly involved with all of the following except A regulation of transcription by extracellular signal molecules B. enzyme activation c activation of G-protein-linked receptors p. activation of protein kinase molecules

Answer 1

the answer to the above question is option A.

REASON: protein phosphorylation involves all the three steps except the first. The addition of one or more phosphate groups causes confirmational changes in an enzyme that can activate or inhibit the enzyme. For example, phosphorylation of the enzyme glycogen synthetase changes the enzyme's shape and reduces its activity.

similarly, Protein kinase molecules are activated by the binding of cyclic AMP , which leads a conformational change. these molecules further phosphoylate other proteins in a phosphorylation cascade (which required ATP hydrolysis).

The G protein linked receptor  are protein kinases which are activated during phosphorylation  that binds extracellular substances and transmits signals from these substances.

thus all steps except A happens during protein phosphorylation.