4. ENERGY-RICH COMPOUNDS
153
As outlined in Table III (cf. also references 341 and 348), later investigations disclosed many exceptions to the above generalization.
Thus, certain species of Annelida were found to have both phosphoarginine and phosphocreatine. However, some closely related genera
of annelids [for example Neanthes and Nereis (343)], and even congeneric species, differed with respect to the type of N-phosphate compound present in the muscle tissue. For example, Glycera gigantea was
shown to have both phosphoarginine and phosphocreatine, whereas G.
convoluta and G. dibranchiata had only phosphocreatine (333). Similar
differences were found in the echinoderms, for example, between the
related echinoids Centrostephanus rodgersii and Heliocidaris erythrogramma (340), and also in the chordates [cf. Balanoglossus davigerus
and B. salmoneus (342-342L·)].
Further investigations disclosed that the tissues of a given animal
may vary with regard to the kind of amidine phosphate present (340,
348). For example, phosphocreatine has been found in ripe sperm, but
not in eggs, muscle, intestine, or immature sperm of the starfish Martliasterias glacialis. Similarly, sperm from the holothurian Leptosynapta
inhaerens, the polychaete Arenicola marina, the sipunculid Sipunculus
nudus and the coelenterate Calliactis parasitica contain phosphocreatine,
whereas the muscle tissues do not (348). Phosphocreatine has also
been found in the testicular tissues of Strongylocentrotus
dröbachiensis
(351, 376) and Sphaerechinus granularis (348), whereas the unfertilized eggs contain phosphoarginine (348, 351).
The muscle tissues of some worms have been found to lack both
phosphocreatine and phosphoarginine, but have either phosphoguanidotaurine, phosphoguanidoacetate, or phosphoguanidoethylserylphosphate.
The latter compound has been isolated only from muscle of the earthworm Lumbricus terrestris. Perhaps the examination of other species of
oligochaetes will disclose that this compound has a wider distribution.
Additional, and as yet unidentified, guanido compounds have also been
found (105, 332, 349) and it is possible that phosphorylated derivatives
of such compounds may function, too, as reservoirs of "energy-rich"
phosphate.
It appears from the above discussion that the distribution of "energy-rich" IV-phosphate compounds in a number of phyla is not constant
and, in fact, varies between related genera, within a genus, and even
between the organs of a single animal. Thus, newer and more extensive
data on the distribution of N-phosphate compounds are not in accord
with the accepted interphyletic relationships. In addition, some of the
phyla examined also have phosphoguanidoacetate, phosphoguanidotaurine, and phosphoguanidoethylserylphosphate. The original generaliza-
153
As outlined in Table III (cf. also references 341 and 348), later investigations disclosed many exceptions to the above generalization.
Thus, certain species of Annelida were found to have both phosphoarginine and phosphocreatine. However, some closely related genera
of annelids [for example Neanthes and Nereis (343)], and even congeneric species, differed with respect to the type of N-phosphate compound present in the muscle tissue. For example, Glycera gigantea was
shown to have both phosphoarginine and phosphocreatine, whereas G.
convoluta and G. dibranchiata had only phosphocreatine (333). Similar
differences were found in the echinoderms, for example, between the
related echinoids Centrostephanus rodgersii and Heliocidaris erythrogramma (340), and also in the chordates [cf. Balanoglossus davigerus
and B. salmoneus (342-342L·)].
Further investigations disclosed that the tissues of a given animal
may vary with regard to the kind of amidine phosphate present (340,
348). For example, phosphocreatine has been found in ripe sperm, but
not in eggs, muscle, intestine, or immature sperm of the starfish Martliasterias glacialis. Similarly, sperm from the holothurian Leptosynapta
inhaerens, the polychaete Arenicola marina, the sipunculid Sipunculus
nudus and the coelenterate Calliactis parasitica contain phosphocreatine,
whereas the muscle tissues do not (348). Phosphocreatine has also
been found in the testicular tissues of Strongylocentrotus
dröbachiensis
(351, 376) and Sphaerechinus granularis (348), whereas the unfertilized eggs contain phosphoarginine (348, 351).
The muscle tissues of some worms have been found to lack both
phosphocreatine and phosphoarginine, but have either phosphoguanidotaurine, phosphoguanidoacetate, or phosphoguanidoethylserylphosphate.
The latter compound has been isolated only from muscle of the earthworm Lumbricus terrestris. Perhaps the examination of other species of
oligochaetes will disclose that this compound has a wider distribution.
Additional, and as yet unidentified, guanido compounds have also been
found (105, 332, 349) and it is possible that phosphorylated derivatives
of such compounds may function, too, as reservoirs of "energy-rich"
phosphate.
It appears from the above discussion that the distribution of "energy-rich" IV-phosphate compounds in a number of phyla is not constant
and, in fact, varies between related genera, within a genus, and even
between the organs of a single animal. Thus, newer and more extensive
data on the distribution of N-phosphate compounds are not in accord
with the accepted interphyletic relationships. In addition, some of the
phyla examined also have phosphoguanidoacetate, phosphoguanidotaurine, and phosphoguanidoethylserylphosphate. The original generaliza-