. The Biochemistry of B vitamins. Vitamins; Vitamin B complex. THE VITAMIN Ba GROUP 661 reported that 2,4,5-trimethyl-3-hydroxypyridine and 2-methyl-3-hy- droxy-4-ethoxymethyl-5-hydroxymethylpyridine inhibited the growth of excised tomato roots, but did not show that the toxicity was prevented by pyridoxine. These and other inhibitory analogues of the vitamin Bc group are listed in Table 37. The analogues, with one exception, contain one or more of the following variations from the structure of pyridoxine: 2-ethyl group replacing the 2-methyl group, a methyl group replacing an hydroxymethyl gr
. The Biochemistry of B vitamins. Vitamins; Vitamin B complex. THE VITAMIN Ba GROUP 661 reported that 2,4,5-trimethyl-3-hydroxypyridine and 2-methyl-3-hy- droxy-4-ethoxymethyl-5-hydroxymethylpyridine inhibited the growth of excised tomato roots, but did not show that the toxicity was prevented by pyridoxine. These and other inhibitory analogues of the vitamin Bc group are listed in Table 37. The analogues, with one exception, contain one or more of the following variations from the structure of pyridoxine: 2-ethyl group replacing the 2-methyl group, a methyl group replacing an hydroxymethyl group, or either an amino or alkyoxyl group replacing an hydroxyl group. These types are illustrated by the following inhibitory analogues: CH2OH I H0:A -CH2OH 2-ethyl-8-hydroxy-4,5-bis (hydroxymethyl)pyridine CH3 I HO—if^'S—CH2OH desoxypyridoxine CH2OCH3 CH2OH. -CH2OH £-methyl-3-hydroxy-4-inethoxymethyl- 5-hydroxymethylpyridine -CH2NH2 2-m ethyl-3-amino-Jf-hydroxy- methyl-5-aminomethylpyridine 2-Ethyl-3-hydroxy-4,5-bis(hydroxymethyl)pyridine. The index at which the ethyl homologue of pyridoxine inhibits the growth of Ceratostomella ulmi is approximately At that ratio of analogue to vitamin, no growth occurs, but at a ratio of 10, approximately half-maximal growth is obtained. This analogue is as effective as pyridoxine in stimulating the growth of excised tomato roots (Table 35).24 This high activity in replac- ing the vitamin for one organism and the very potent inhibiting action on another organism illustrate that a line of demarkation cannot be drawn between stimulatory and inhibitory properties of analogues of metabolites. Desoxypyridoxines. Investigation of the vitamin activity of analogues of pyridoxine led to the discovery that 2,4-dimethyl-3-hydroxy-5-hy- droxymethylpyridine (a desoxypyridoxine) was very toxic for pyridoxine- deficient Day-old female single comb White Leghorn chicks, after being maintained on an adequate diet for three days, were pla
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