CHEMISTRY OF RIBOSE AND DEOXYRIBOSE 35 



selves, but also to substances containing either of them as a molecular 

 component.^'^ Table IV includes values calculated for the velocity con- 

 stant {K X 10^) for the acidic hydrolysis of ribose phosphates, and for, 

 comparison some xylose phosphates are included. 



Details concerning the alkaline hydrolysis of pentose phosphates are 

 somewhat more scanty. Measurements of specific rotations have been used 

 for distinguishing between ribose-3- and -5-phosphates and other pentose 

 phosphates. In Table V values of the specific rotation for various pentose 

 phosphates are listed. 



Klimek and Parnas'*- distinguished between adenylic acids possessing 

 ribose-3- and -5-phosphate moieties by a method based on the formation 

 of a blue soluble complex by adenosine-5'-phosphate in alkaline solution 

 in the presence of copper sulfate. Under the same conditions only an in- 

 soluble precipitate is formed by adenosine-3'-phosphate, which after 

 centrifuging leaves a clear colorless supernatant solution. The procedure 

 was standardized more completely l)y Berlin and Westerberg.'^^ Albaum and 

 Umbreit'"^ have developed a method for differentiating between ribose-3- 

 and -5-phosphates and compounds containing them, by means of the 

 orcinol pentose color reaction. The method is rapid and can be used on as 

 low an amount as 10 ^g. of phosphate ester. It cannot be used precisely on 

 crude plant and bacterial extracts containing polysaccharides, since these 

 alter the rate of color development. Paper chromatography provides a val- 

 uable micromethod for the identification of sugar-phosphate esters. '^''"'^^ 

 Some Rf values of ribose phosphates and other pentose phosphates, as 

 quoted by Cohen and McNair Scott, '^^ are shown in Table VI. 



The addition of boric acid to the solvents retards the movement of 

 ribose-5-phosphate compared with arabinose-5-phosphate, an effect at- 

 tributed to the combination of boric acid with the cfs-hydroxyl groups 

 attached to C-2 and C-3 in ribose. Ribose phosphates may be separated 

 from other sugar phosphates by ion-exchange resin chromatography. 

 [Cf. Cohn, Chapter 6.] Horecker and Smyrniotis'^* used Dowex 1 formate 

 for the separation of pentose phosphates resulting from the action of a 

 yeast enzyme on 6-phosphogluconate. Sugar phosphates have also been 



'82 R. Klimek and J. K. Parnas, Biochem. Z. 252, 392 (1932). 



183 H. Berlin and J. Westerberg, Z. phijsiol. Chan. 281, 98 (1944). 



184 C. S. Hanes and F. A. Isherwood, Nature 164, 1107 (1949). 

 186 S. S. Cohen and D. B. McNair Scott, Science 111, 543 (1950). 



186 R. S. Bandurski and B. Axelrod, J. Biol. Chem. 193, 405 (1951). 



187 A. A. Benson, J. A. Bassham, M. Calvin, T. C. Goodale, V. A. Haas, and W. 

 Stepka, /. Am. Chem. Soc. 72, 1710 (1950). 



'88 (a) B. L. Horecker and P. Z. Smyrniotis, Arch. Biochem. and Biophys. 29, 

 232 (1950) ; see also (b) B. L. Horecker, P. Z. Smyrniotis, and J. E. Seegmiller, J. 

 Biol. C/iem. 193, 383 (1951). 



