Problem of the reactive species from enzymic and chemical oxidations of o-diphenols: anomalies in the trapping of o-quinonoids with benzenesulphinic acid.

These indicate that in crabs adapted to 850 mosmolal condition, the glutamate, proline and glycine oxidation rates are similar in terms of pmol consumed per unit time, although the lower number of C atoms in glycine means that it enables only 40% as much ADP to be phosphorylated to ATP as the other two amino acids do. When the salinity is decreased, however, the contribution of glycine C to COz produced increases nearly fivefold, now being equal to glutamate and proline, even though the oxidation of both these amino acids has also increased. Thusglycineappears to occupy a special position in terms of the provision of additional oxidizable C during adaptation to a decreased environmental salinity by Carcinus maenas. Preliminary data on species of Maia and of Portunas suggest that a similar situation may apply, although their tolerance to changes in external salinity is much less. The euryhaline teleost Agonus cataphracfus, however, does not appear to increase glycine oxidation during adaptation to a lowered environmental salinity.