Adenosine 5 -triphosphate substrate level phosphorylation

Substrate-level phosphorylation. Prodnction of adenosine triphosphate (ATP) by the direct transfer of a high-energy phosphate molecnle to adenosine diphosphate (ADP) dnring catabolism of a phosphorylated organic componnd. It occurs under both aerobic and anaerobic conditions. 

The ready reversibility of the kinases and their abundance in cells has the result that all of the free nucleoside phosphates in a cell reflect the relative amounts of the adenosine phosphates in each of the three levels of phosphorylation. Because the adenosine phosphates are primarily involved in energy metabolism, the energy status of the cell is reflected in the relative amounts of ATP, ADP, and adenylate. Through the very facile transphosphorylation reactions, other nucleoside phosphates become similarly distributed among the three levels of phosphorylation perturbations in energy metabolism, such as those caused by substrate deprivation or by anoxia, cause parallel shifts in the relative amounts of the mono-, di-, and triphosphates in all of the nucleotide families. 

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