Mikrobiologische Synthese der Folinsäure aus 2-Amino-6-oxy-pteridinaldehyd-8 und p-Aminobenzoyl-l-glutaminsäure

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Abstract
The authors obtained growth matching that obtainable by use of folic acid, by using adapted strains of Streptococcus faecalis supplied only with combinations of 2-amino-6-hydroxypteridinaldehyde-8 (Aldehyde), or 2-amino-6-hydroxy 8-d-arabo-tetrahydroxybutylpteridine on the one hand, and p-aminobenzoyl-l-glutamic acid (ABG) or p-aminobenzoic acid (PABA), thus demonstrating the biosynthesis of folic acid from Aldehyde and ABG. Inhibition of growth due to antagonism between Aldehyde and tetrahydroxybutyl compounds on the one hand, and folic acid on the other, has now been observed in still other folic acid-requiring bacteria, including strains of Lacto-bacillus helveticus, S. thermophilus, S. anhemolvticus, Betacoccus arabinosus. and Staphylococcus aureus. In other bacterial strains without folic acid requirements, on the contrary, (Streptobacterium plantarum, Staphylococcus aureus, Proteus vulgaris. and Escherichia coli) no inhibition ascribable to adequate folic acid synthesis was observed on addition of Aldehyde to the folic-acid free medium. Aldehyde-folic acid antagonism can be demonstrated for Streptococcus faecalis also, by use of pteroic acid, rhizopterin, formylfolic acid, and teropterin, but not by thymine. Adaptation expts. with S. faecalis, S. thermophilus. and enterococcus consist of testing the growth-promoting action of ABG plus Aldehyde in synthetic nutrient solns., the inhibitory action of Aldehyde against folic acid, and the inhibitory effect of Aldehyde alone after each inoculation passage, showing that only Aldehyde conditions adaptation and that adapted strains differ from others not morphologically, but only in respect to the acceleration of their growth by like concns. of folic acid. Under otherwise similar conditions production of similar effects required 4 times the quantity of the tetrahydroxybutyl compound when this was substituted for Aldehyde, while ABG was somewhat more effective than PABA. The growth substances synthesized from these above-mentioned raw materials were isolated from the cultures and identified as folic acid and pteroic acid. Adapted strains grew, in contrast to the initial material, even in folic acid-containing medium, upon addition of Aldehyde or of the tetrahydroxybutyl compound. The findings offer no support for the hypothesis published by Forrest and Walter, but afford some for Tschesche''s suggestion.