4. ENERGY-RICH COMPOUNDS
129
d. Distribution. ATP and other nucleoside 5'-polyphosphates have
been identified unambiguously by Chromatographie methods in acid
extracts of the following tissues: rat organs (62, 93-95b), guinea pig
mammary gland (96), human erythrocytes (97-97c), yeast (98-100),
Lactobacillus arabinosus (101), eggs of the sea urchin Psammechinus
miliaris (102), flight muscles of the housefly Musca domestica (103,
104), body wall of the earthworm Lumbricus terrestris (105), the
pharynx muscle of the snail Helix pomatia (106), the sartorius muscle
of the tortoise Testudo graeca (106), muscle of frog (106), squid
(107), and carp (108), and plant tissues (91i). Other methods have
been employed for the identification of ATP in a wide variety of
tissues and cells, too numerous to document in extenso. There seems
little doubt, however, that ATP is the most important "energy-rich"
compound in the entire phyletic sequence, as evidenced by its seemingly universal distribution in animals, plants, and microorganisms.
Even in living systems where ATP has not yet been specifically identified, the existence of any of the following metabolic sequences may
be taken as presumptive evidence for the concomitant existence of
ATP: glycolysis, pentose cycle, citric acid cycle, urea cycle, fatty acid
oxidation and synthesis, protein synthesis, and nucleic acid synthesis.
Furthermore, as illustrated in Section III of this chapter, the identification of other "energy-rich" compounds in a living system, again implies
the presence of ATP because of known enzymatic reactions that involve
the interaction of these compounds with ATP.
2. Inorganic Poly phosphates
a. Preparation and Identification. The general term "polyphosphates" includes both linear and cyclic anhydrides of inorganic phosphate. The structures of the most commonly encountered low molecular weight members (pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrametaphosphate) are shown in Fig. 6. Of these compounds, only pyrophosphate and tripolyphosphate have been investigated extensively. High molecular weight polymers, consisting of either
linear or cyclic units, or mixed polymers, have been prepared synthetically. A linear polyphosphate is shown in Fig. 6. In biological systems the structural sub-unit of the high molecular weight polymers
cannot be identified with certainty (109, 110); consequently, we shall
use the term "polyphosphate" for all polymerized structures even
though they may have been designated as metaphosphates in the
original citations.
Polyphosphates are found in many cells, the first isolation from
yeast being reported by Liebermann in 1888 (111). Standard fractiona-
129
d. Distribution. ATP and other nucleoside 5'-polyphosphates have
been identified unambiguously by Chromatographie methods in acid
extracts of the following tissues: rat organs (62, 93-95b), guinea pig
mammary gland (96), human erythrocytes (97-97c), yeast (98-100),
Lactobacillus arabinosus (101), eggs of the sea urchin Psammechinus
miliaris (102), flight muscles of the housefly Musca domestica (103,
104), body wall of the earthworm Lumbricus terrestris (105), the
pharynx muscle of the snail Helix pomatia (106), the sartorius muscle
of the tortoise Testudo graeca (106), muscle of frog (106), squid
(107), and carp (108), and plant tissues (91i). Other methods have
been employed for the identification of ATP in a wide variety of
tissues and cells, too numerous to document in extenso. There seems
little doubt, however, that ATP is the most important "energy-rich"
compound in the entire phyletic sequence, as evidenced by its seemingly universal distribution in animals, plants, and microorganisms.
Even in living systems where ATP has not yet been specifically identified, the existence of any of the following metabolic sequences may
be taken as presumptive evidence for the concomitant existence of
ATP: glycolysis, pentose cycle, citric acid cycle, urea cycle, fatty acid
oxidation and synthesis, protein synthesis, and nucleic acid synthesis.
Furthermore, as illustrated in Section III of this chapter, the identification of other "energy-rich" compounds in a living system, again implies
the presence of ATP because of known enzymatic reactions that involve
the interaction of these compounds with ATP.
2. Inorganic Poly phosphates
a. Preparation and Identification. The general term "polyphosphates" includes both linear and cyclic anhydrides of inorganic phosphate. The structures of the most commonly encountered low molecular weight members (pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrametaphosphate) are shown in Fig. 6. Of these compounds, only pyrophosphate and tripolyphosphate have been investigated extensively. High molecular weight polymers, consisting of either
linear or cyclic units, or mixed polymers, have been prepared synthetically. A linear polyphosphate is shown in Fig. 6. In biological systems the structural sub-unit of the high molecular weight polymers
cannot be identified with certainty (109, 110); consequently, we shall
use the term "polyphosphate" for all polymerized structures even
though they may have been designated as metaphosphates in the
original citations.
Polyphosphates are found in many cells, the first isolation from
yeast being reported by Liebermann in 1888 (111). Standard fractiona-