The AMP deaminase of the mollusk Helix pomatia is an unexpected member of the adenosine deaminase-related growth factor (ADGF) family

We report here the first occurrence of an adenosine deaminase-related growth factor (ADGF) that deaminates adenosine 5' monophosphate (AMP) in preference to adenosine. The ADGFs are a group of secreted deaminases found throughout the animal kingdom that affect the extracellular concentration of adenosine by converting it to inosine. The AMP deaminase studied here was first isolated and biochemically characterized from the roman snail Helix pomatia in 1983. Determination of the amino acid sequence of the AMP deaminase enabled sequence comparisons to protein databases and revealed it as a member of the ADGF family. Cloning and expression of its cDNA in Pichia pastoris allowed the comparison of the biochemical characteristics of the native and recombinant forms of the enzyme and confirmed they correspond to the previously reported activity. Uncharacteristically, the H. pomatia AMP deaminase was determined to be dissimilar to the AMP deaminase family by sequence comparison while demonstrating similarity to the ADGFs despite having AMP as its preferred substrate rather than adenosine.

Automated summary

We report the discovery of a novel adenosine deaminase-related growth factor (ADGF) that specifically deaminates adenosine 5' monophosphate (AMP) rather than adenosine. ADGFs are secreted deaminases that regulate extracellular adenosine concentration by converting it to inosine. The AMP deaminase studied in this research was first identified and characterized from the snail Helix pomatia in 1983. Through sequence comparison and protein expression, it was determined that this AMP deaminase is a member of the ADGF family despite its preference for AMP over adenosine.