4. ENERGY-RICH COMPOUNDS
149
phocreatine, has been determined colorimetrically (345), or by reaction
with creatine phosphokinase (345a). Phosphocreatine can also be converted to creatinine by a reaction with acid molybdate (346). Separation
of phosphate esters chemically (336, 347) or by passage through an
ion exchange resin (348, 349) has been used to provide sufficient
OH
I
HN
P=0
I
I
HN=C
OH
I
N—CH-C00H
CH3
Phosphocreatine
OH
I
HN—P=0
HN= C
0H
HN—CHg— (CH2)JTCH—COOH
NH2
Phosphoarginine
OH
I
HN—P=0
I OH
HN = C
I
OH
I
HN—P=0
I OH
HN = C
I
Phosphoguanidotaurine
Phosphoguanidoacetate
HN—P=0
I
I
HN=C OH
OH
I
HN— CH9-CH«-0—P-O-CHg-CH COOH
2
2
II
2
I
0
ΝΗ9
Phosphoguanidoethylseryl phosphate
FIG. 10. Amidine phosphates.
concentration of phosphocreatine to permit determination of the phosphate : creatine ratio. Both phosphocreatine and creatine can be identified by means of paper chromatography (336, 340, 349, 350).
Concentration of phosphoarginine by chemical methods (351) or
by ion exchange resins (341) has also been successful and fractions
obtained by these methods have been analyzed (351) for the phosphate:
arginine ratio. Arginine can be determined colorimetrically by the
Weber modification (352) of the Sakaguchi method, or by reaction