SUBSTANCES PRODUCED BY FUNGI 207 



The penicillins are strong monobasic acids of fK about 2.8. On treat- 

 ment with hot dilute mineral acids, penicillins give i molecule of COo, 

 an amino acid (penicillamine) and other products. The penicillamine 

 (^-(3,(3-dimethylcysteine) belongs to the d or "unnatural" series of 

 a-amino acids. Penicillin G yields on hydrolysis phenaceturic acid, 

 phenylacetamide, and an aldehyde, CiqHuOoN. Phenylacetic acid was 

 also identified as a hydrolytic product. 



The acidic group of penicillin was found to be identical with the 

 carboxyl group in penicillamine j the addition of water to penicillin 

 gives a second carboxyl j the new carboxyl breaks down to COo by the 

 action of hot dilute mineral acid. The dicarboxylic acid thus produced, 

 designated as penicilloic acid, is presumably the product of the action 

 of penicillinase on penicillin. 



The molecular weight of penicillin ranges from 490 to 510. 



Penicillin is very unstable, especially in acid solutions and in an iso- 

 lated form. 



Penatin 



P. notatum produces, in addition to penicillin, a second antibacterial 

 substance designated as E. coli factor, penatin, notatin, and penicillin B. 

 This substance is a flavo-protein and acts as a glucose-oxidase, oxygen 

 being required. It is characterized by its action not only upon gram- 

 positive but also upon many gram-negative bacteria, and by the fact that 

 the presence of glucose is required for its activity. Its action is inhibited 

 by the presence of catalase (157, 517, 786). 



Flavian 



Flavicin, a substance similar in every respect to penicillin, is pro- 

 duced by A. flavus (950) j another substance, gigantic acid, is produced 

 by A . giganteus {"]ii). Preparations of flavicin have also been designated 

 as flavatin (748),aspergillin (103, 876), and flavacidin (606). This sub- 

 stance was found to be largely penicillin F, with a potency of 1,400 

 O.U./mg. against S. aureus and a B. subtilis-S. aureus ratio of 0.72. 

 The variable R group in the general penicillin formula is represented by 

 — CHo.CHo.CH^CH.CHg. A small amount of penicillin G (R = 

 — CHo.CgHg) was also detected (299). 



