356 



RIBOFLAVIN 



biotic, notatin.^^ The enzyme apparently occurs in many fungi. This en- 

 zyme shows a pronounced specificity for ghicose^^ and has very little or no 

 activity for about fifty other sugars tested. 



H 



OH 



C 



I 

 HCOH 



HOCH O + O2 + H2O 



I 

 HCOH 



I 

 HC 



I 

 HC— OH 



H 

 D-Glucose 



COOH 



I 

 HCOH 



I 

 HOC— H 



I 

 -> HC— OH +H2O2 



I 

 HC— OH 



I 

 HC— OH 

 H 



D-Gluconic acid 



Methylene blue cannot be used instead of oxygen. If hydrogen sulfide^^ 

 is added to poison the catalase in crude extracts, there is a quantitative 

 formation of hydrogen peroxide. 



15. HiSTAMINASE, DiAMINO OXIDASE 



The flavoprotein nature of histaminase was first noted by Swedini""- 101 

 in 1943, but a subsequent report by Leloir and Green^^^ (jj(j ^ot confirm 

 his findings. Kapeller-Adler^''^ has presented evidence to show that this 

 enzyme prepared from hog kidney contains flavin adenine dinucleotide. 



This flavoprotein will catalyze the oxidation of di- and polyamines to 

 amino aldehydes. Although it has a much higher affinity for histamine, 

 it will also act on cadaverine, putrescine, and agmatine. 



According to Zellerj^"^- ^"^ the action of histaminase is represented as 

 follows : 



R— CH2NH2 + O2 + H2O -> ECHO + NH3 + H2O2 



" C. E. Coulthard, R. Michaelis, W. F. Short, G. Sykes, G. E. H. Skrimshire, A. F. 

 B. Standfast, J. H. Birkinshaw, and H. Raistrick, Biochem. J. 39, 24 (1945). 



98 K. Keilin and E. F. Hartree, Biochem. J. 42, 221 (1948). 



99 W. Franke and F. Lorenz, Ann. 532, 1 (1937). 



100 B. Swedin, Acta Med. Scand. 114, 210 (1943). 



101 B. Swedin, Arkiv Kemi. Mineral. Geol. 17A, 27 (1944). 



102 L. F. Leloir and D. E. Green, Federation Proc. 5, 144 (1946). 



103 R. Kapeller-Adler, Biochem. J. 44, 70 (1949). 

 lo" E. A. Zeller, Helv. Chim. Acta 21, 880 (1938). 

 •06 E. A. Zeller, Advances in Enzymol. 2, 93 (1942). 



