4. ENERGY-RICH COMPOUNDS
135
in addition, varying amounts of polyphosphate, pyrophosphate, and
tripolyphosphate were found (158, 159). Production of the polyphosphates in the intestinal lumen by the action of bacteria seems to have
been ruled out, at least as the sole mechanism of formation, since urine
collected directly from the Malpighian tubules and the meconium of
the imago also contained polyphosphates. An accumulation of pyrophosphate has also been reported to occur in the ejaculatory duct of
the hawk-moth, Celerio euphorbiae (160, 160a), and to be transferred
to the female during copulation (160a). Experiments with labeled ATP
showed that pyrophosphate was produced in the male organ by apyrase
action (Reaction 27) and accumulated there owing to the absence of
pyrophosphatase (160b).
3. Acyl Phosphates
a. Acetyl and Other Carboxyl Phosphates:
(1). Preparation and identification. The structure of a representative carboxyl phosphate, acetyl phosphate, is given in Fig. 7. Other
carboxyl phosphates may be formed by bacteria, plants, and animal
tissues. For example, butyryl (161, 162), propionyl (162, 163), carbamyl (164^-165a), and aspartyl (166) phosphates have been isolated, and some evidence concerning the possible existence of carbonyl
(167), succinyl (163, 168, 169), and glutamyl (170) phosphates has
been presented. In the following discussion, attention will be directed
primarily to acetyl phosphate because it is the most widely encountered
and best-documented member of this class of "energy-rich" compounds.
Acetyl phosphate was first isolated by Lipmann (171, 172), as an
end product in the phosphate-dependent oxidation of pyruvate by
Lactobacillus delbrueckii (173). Analysis of other phosphate-dependent
pyruvate degradations indicated that several bacterial systems were
capable of producing acetyl phosphate (174-176). Such degradations
were termed "phosphoroclastic reactions" (172, 177). Chemical synthesis of acetyl phosphate may be accomplished by the reaction of: (a)
acetyl chloride with silver dibenzyl phosphate (178); (b) acetyl chloride with silver dihydrogen phosphate (179); (c) isopropenyl acetate
with orthophosphoric acid (180, 181); and (d) acetic anhydride with
orthophosphate in aqueous pyridine (182). The fourth method is essentially quantitative and has been used, after slight modification (110),
to prepare P
32 -labeled acetyl phosphate. The second and fourth methods have also been used to prepare propionyl (179), butyryl (179),
and succinyl (169, 179) phosphates.
The lability of acyl phosphates in acid molybdate has been utilized
135
in addition, varying amounts of polyphosphate, pyrophosphate, and
tripolyphosphate were found (158, 159). Production of the polyphosphates in the intestinal lumen by the action of bacteria seems to have
been ruled out, at least as the sole mechanism of formation, since urine
collected directly from the Malpighian tubules and the meconium of
the imago also contained polyphosphates. An accumulation of pyrophosphate has also been reported to occur in the ejaculatory duct of
the hawk-moth, Celerio euphorbiae (160, 160a), and to be transferred
to the female during copulation (160a). Experiments with labeled ATP
showed that pyrophosphate was produced in the male organ by apyrase
action (Reaction 27) and accumulated there owing to the absence of
pyrophosphatase (160b).
3. Acyl Phosphates
a. Acetyl and Other Carboxyl Phosphates:
(1). Preparation and identification. The structure of a representative carboxyl phosphate, acetyl phosphate, is given in Fig. 7. Other
carboxyl phosphates may be formed by bacteria, plants, and animal
tissues. For example, butyryl (161, 162), propionyl (162, 163), carbamyl (164^-165a), and aspartyl (166) phosphates have been isolated, and some evidence concerning the possible existence of carbonyl
(167), succinyl (163, 168, 169), and glutamyl (170) phosphates has
been presented. In the following discussion, attention will be directed
primarily to acetyl phosphate because it is the most widely encountered
and best-documented member of this class of "energy-rich" compounds.
Acetyl phosphate was first isolated by Lipmann (171, 172), as an
end product in the phosphate-dependent oxidation of pyruvate by
Lactobacillus delbrueckii (173). Analysis of other phosphate-dependent
pyruvate degradations indicated that several bacterial systems were
capable of producing acetyl phosphate (174-176). Such degradations
were termed "phosphoroclastic reactions" (172, 177). Chemical synthesis of acetyl phosphate may be accomplished by the reaction of: (a)
acetyl chloride with silver dibenzyl phosphate (178); (b) acetyl chloride with silver dihydrogen phosphate (179); (c) isopropenyl acetate
with orthophosphoric acid (180, 181); and (d) acetic anhydride with
orthophosphate in aqueous pyridine (182). The fourth method is essentially quantitative and has been used, after slight modification (110),
to prepare P
32 -labeled acetyl phosphate. The second and fourth methods have also been used to prepare propionyl (179), butyryl (179),
and succinyl (169, 179) phosphates.
The lability of acyl phosphates in acid molybdate has been utilized