PT  - JOURNAL ARTICLE
AU  - Fouts, James R.
AU  - Kamm, Jerome J.
AU  - Brodie, Bernard B.
TI  - ENZYMATIC REDUCTION OF PRONTOSIL AND OTHER AZO DYES
DP  - 1957 Jul 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 291--300
VI  - 120
IP  - 3
4099  - http://jpet.aspetjournals.org/content/120/3/291.short
4100  - http://jpet.aspetjournals.org/content/120/3/291.full
SO  - J Pharmacol Exp Ther1957 Jul 01; 120
AB  - Prontosil and a variety of azo dyes are reductively cleaved in the rabbit by an enzyme system present predominantly in liver. The azo reductase system is localized mainly in the soluble fraction of the cell, but is also present in microsomes. TPNH serves as the hydrogen donor, DPNH having virtually no activity. The system is markedly accelerated by an excess of riboflavin, FMN or FAD and is probably a flavoprotein. It is proposed that flavins act in at least two ways in the system: 1) as the prosthetic group and 2) as an unbound hydrogen transport system similar to a coenzyme. The accelerating effect of flavins would be due to their acting in this latter property. Evidence is presented which shows that azo reductase and nitro reductase, though similar in many respects, are different enzyme systems.