ATPssä

ATPssä is a term used in speculative biochemistry and in science fiction worldbuilding to denote a hypothetical energy-carrying nucleotide-like molecule. Described as an alternative to adenosine triphosphate (ATP), ATPssä is imagined to function as the primary energy currency in certain organisms or systems, storing energy in high-energy phosphate bonds and releasing it upon hydrolysis to drive cellular processes.

In proposed models, ATPssä combines a ribose-linked base similar to adenine with a phosphate architecture that extends beyond the standard triphosphate chain, such as a tetraphosphate or a modified phosphate linkage. This configuration is said to alter the molecule’s hydrolysis potential and the rate constants of phosphoanhydride cleavage, potentially providing different energy yields and regulatory dynamics compared with ATP.

Hypothetical organisms proposed in these models might use ATPssä in place of ATP for phosphorylation reactions, with specialized kinases and phosphatases adapted to recognize the ATPssä molecule. The imagined benefits include greater stability under extreme temperatures, resistance to nonspecific hydrolysis, or tunable energy release suitable for rapid or prolonged cellular responses.

At present, ATPssä has no empirical evidence in real biochemistry. It is primarily discussed in theoretical treatments and fictional settings, serving as a conceptual tool to explore alternative energy currencies and enzyme specificity. It is commonly contrasted with ATP, GTP, and other high-energy phosphates in discussions of cellular energetics.