ANALOGS OF RIBOFLAVIN AND FAD 547 



be the most commonly used detector for the participation of flavins in 

 enzyme systems, but before this is subjected to analysis we shall discuss 

 some of the results which have been obtained. The following summary pre- 

 sents the data reported on antagonism but does not in any case imply a 

 truly competitive mechanism. 



Enzymes in which inhibition is reduced by FMN or FAD 



Adenosinetriphosphatase (mitochondrial NAD-activated): FMN and FAD 

 (Low, 1959) 



Aldehyde oxidase (rat and monkey liver): FAD (Lakshmanan et al., 1964; 

 Mahadevan et al, 1962) 



Aliesterase (liver): FMN (Hemker and Hiilsman, 1960) 



D- Amino acid oxidase (lamb and sheep kidney): FAD (Hellerman et al., 

 1946; Burton. 1951 a) 



Catechol oxidase (spinach): FAD (Nair and Vining, 1964) 



Choline dehydrogenase (rat liver): FAD (Bargoni, 1963) 



Cytochrome reductase: FMN (Haas, 1944) 



Hydroxylamine: cytochrome c oxidoreductase {Nitrosomonas): FMN and 

 FAD (Aleem and Lees, 1963) 



Lactate dehydrogenase {Lactobacillus and yeast): FMN and FAD (Snos- 

 well, 1959; Iwatsubo and Labeyrie, 1962) 



NADH: nitrite oxidoreductase (Neurospora): FAD (Nicholas et al., 1960) 



NADH oxidase {Azotobacter, Clostridium, and Lactobacillus): FAD (Re- 

 paske and Josten, 1958; Dolin, 1959; C. F. Strittmatter, 1959) 



Nitrate reductase (Pseudomonas): FAD (Fewson and Nicholas, 1961) 



Succinate oxidase {Tetrahyrnena and Xanthomonas): FMN and FAD (Ei- 

 chel, 1956 b; Madsen, 1960) 



Enzymes in which inhibition is not reduced by FMA or FAD 



Adenosinetriphosphatase (mitochondrial sonicate) (Beyer, 1960) 



Allohydroxy-D-proline oxidase {Pseudomonis) (Yoneya and Adams, 1961) 



L-Amino acid oxidase (moccasin venom) (Singer and Kearney, 1950) 



Ethanolamine oxidase (Arthrobacter) (Narrod and Jakoby, 1964) 



L-Galactono-5^-lactone dehydrogenase (cauliflower) (Mapson and Bres- 

 low, 1958) 



Lactate dehydrogenase (Propionibacteritim) (Molinari and Lara. 1960) 



Nitrate reductase {E. coli) (Heredia and Medina, 1960) 



Old yellow enzyme (yeast) (Kistner, 1960) 



