. The Biochemistry of B vitamins. Vitamins; Vitamin B complex. THE FOLIC ACID GROUP 589 Mallette, Taylor and Cain 141 was extremely effective in inhibiting the growth of Streptococcus faecalis R. The effects of these pteridines and related compounds on a number of organisms are indicated in Table 21. The inhibitory effects of these pteridines are prevented in a competitive manner by folic acid, particularly for Streptococcus faecalis R. The most effective inhibitors of these pteridines are those with aromatic substitu- ents in the 6,7-positions, , 2,4-diamino-6,7-diphenylpteridine, 2,4- di
. The Biochemistry of B vitamins. Vitamins; Vitamin B complex. THE FOLIC ACID GROUP 589 Mallette, Taylor and Cain 141 was extremely effective in inhibiting the growth of Streptococcus faecalis R. The effects of these pteridines and related compounds on a number of organisms are indicated in Table 21. The inhibitory effects of these pteridines are prevented in a competitive manner by folic acid, particularly for Streptococcus faecalis R. The most effective inhibitors of these pteridines are those with aromatic substitu- ents in the 6,7-positions, , 2,4-diamino-6,7-diphenylpteridine, 2,4- diaminophenanthro(9,10-e)pteridine and 2,4-diaminoacenaphtho(l,2-e)- pteridine. NH2 A n jTx I H2N—C C C N C C N N 2,4-diamino-6,7-diphenylpteridine f\. 2,4,-diamino-6,7-phenanthro(9,10-e)pteridine A large number of the pteridines indicated in Table 21 were prepared in an effort to find more soluble derivatives with the same potent in- hibitory properties as the 2,4-diaminopteridines with 6,7-aromatic sub- stituents. However, substitution of the aromatic groups lowered the activity, regardless of the nature of the substituent group. Acetylation of the 2- or 4-amino groups did not appreciably alter the activity, but methylation of these amino groups resulted in considerable loss of in- hibitory The 2,4-diaminopteridines contrast markedly with the 2-amino-4- hydroxypteridines which, though more closely related structurally to folic acid, do not possess antibacterial activity; on the contrary, some have very slight growth-stimulating 2,4-Diamino-6,7-diphenylpteridine inhibits the growth of Lactobacillus arabinosus, which does not require exogenous folic Both p-amino-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Williams, Roger John, 1893-. New York : Reinhold Pub. Corp.
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