Glycolysis: GTP for Substrate Level ATP Synthesis in Plants

[Suraj M]

in substrate level ATP synthesis in glycolysis.. why is GTP used as an intermediate for ATP synthesis( succinyl-CoA to succinic acid)

 

[Zefram]

As a scientist, I would like to clarify that GTP (guanosine triphosphate) is not directly used as an intermediate for ATP synthesis in the conversion of succinyl-CoA to succinic acid in glycolysis. Instead, the molecule GDP (guanosine diphosphate) is generated as an intermediate, which is then converted to GTP in a separate reaction.

The conversion of succinyl-CoA to succinic acid in glycolysis involves the enzyme succinyl-CoA synthetase, which catalyzes the transfer of a phosphate group from succinyl-CoA to GDP, forming GTP and succinic acid. This GTP is then used as a substrate by another enzyme, nucleoside diphosphate kinase, which transfers a phosphate group from GTP to ADP, forming ATP.

The use of GTP as an intermediate in this reaction is important because it allows for the transfer of a high-energy phosphate group from succinyl-CoA to GDP, which can then be used to generate ATP. This is a more efficient process than directly transferring the phosphate group to ADP, as it allows for the production of two molecules of ATP per molecule of succinyl-CoA, rather than just one.

Additionally, the use of GTP as an intermediate in this reaction also helps to maintain the balance of nucleotides in the cell. Since GDP is constantly being generated in other cellular processes, the use of GTP as an intermediate ensures that there is a constant supply of GTP available for ATP synthesis.

In summary, GTP is not directly used as an intermediate for ATP synthesis in the conversion of succinyl-CoA to succinic acid in glycolysis. Instead, it is used indirectly to transfer a high-energy phosphate group to ADP, resulting in the production of ATP. This process is more efficient and helps to maintain the balance of nucleotides in the cell.