Through its function as a catalyst for the hydrolysis of phosphoarginine
to yield ATP, AK could contribute to the energetic requirement for the active transport of ions during osmoregulation (Towle & Weihrauch 2001, Holt & Kinsey 2002).
We find this quality-control system, organized around a distinct protein phospho mark (phosphoarginine
, pArg), a fascinating model to investigate novel principles of dealing with proteotoxic stress.
This increase on day 1 may be due to the regeneration of ATP through the action of the adenylate kinase enzyme, or to the utilization of the phosphoarginine
phosphagen in a reaction catalyzed by the arginine kinase enzyme, as has been reported for other species, such as the abalone Haliotis discus (Watanabe et al., 1992) and the scallop Zygochlamys patagonica (Massa et al, 2001).
The attacking nucleophile need not be a nucleotide, because phosphoarginine
and phosphogluconate can also cap an RNA catalyst.
Arginine kinase belongs to a class of kinases that plays a role in the maintenance of ATP levels by the phosphorylation of phosphoarginine
in a wide variety of invertebrates, which then serves as a high energy source from which ATP can be rapidly replenished (Uda et al.
Force production during escape responses by Placopecten magelanicus is a sensitive indicator of handling stress: comparison with adductor muscle adenylate energy charge and phosphoarginine
is commonly referred to as a phosphagen and represents an intermediate storage and transport form of energy in a wide variety of invertebrates.