Final answer:
The valid kinase catalyzed reactions from the provided list are a) ATP + GDP → ADP + GTP and d) AMP + ATP → 2 ADP. In option a), a phosphate group is transferred from ATP to GDP, and in option d), from ATP to AMP.
Step-by-step explanation:
The question asks which of the listed reactions are valid kinase catalyzed reactions involving the transfer of a phosphoryl group from a nucleoside triphosphate. A kinase is an enzyme that catalyzes the transfer of a phosphate group from one molecule to another. The reactions provided are all feasible in the context of kinase activity, but they differ based on which nucleoside triphosphate is involved. Let's analyze them one by one.
- a) ATP + GDP → ADP + GTP: This reaction is valid. A kinase catalyzes the transfer of a phosphate group from ATP to GDP, forming ADP and GTP.
- b) AMP + GMP → AMP + GTP: This reaction is not valid as AMP cannot donate a phosphate group it doesn't have, and kinases typically transfer phosphate to ADP or another diphosphate, not AMP.
- c) ADP + CMP → AMP + CDP: This reaction is not valid as kinases typically catalyze the transfer of phosphate to ADP, forming ATP, rather than converting ADP to AMP.
- d) AMP + ATP → 2 ADP: This reaction is valid. Here, a kinase transfers a phosphate group from ATP to AMP, creating two molecules of ADP.
Therefore, the valid kinase catalyzed reactions from the provided options are a) and d).