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[Effect of riboflavin analogs on Pichia guilliermondii growth]
Abstract:
The work was aimed at studying the biological activity of 32 structural riboflavin (RF) analogs substituted at positions 7, 8 and 10 as well as with a modified structure of the isoalloxazine cycle and the side D-ribityl chain. An RF-dependent mutant of the yeast Pichia guilliermondii MS1 was used as a test organism. The strain could grow in a medium without the vitamin in the presence of 2-thio-RF and analogs with esterified hydroxyls in the side chain, viz. tetraacetate and tetrabutyrate of RF. The antagonistic properties were distinctly displayed only by D-ribityl derivatives of vitamin B2 with a substitution of CF3, Cl, H, NH2 and N(CH3)2 for one or the both methyl groups. The inhibition indices for such analogs varied from 0.52 to 10.8. The action of the antivitamins on the yeast growth was competitively eliminated by adding RF to the growth medium. The antivitamin activity of an analog abruptly decreased or disappeared if (i) a bulky substituent such as N-piperidyl or hydroxyethylamine was incorporated at position 8 of an antimetabolite molecule, (ii) the D-ribityl side chain was substituted by a D-galactyl, D-sorbityl, L-ramnityl, 2-hydroxyethyl or methyl group and (iii) the structure of isoalloxazine cycle was modified. The analogs which were phosphorylated by RF kinase (ATP: RF-5'-phosphotransferase, EC 2.7.1.26) from P. guilliermondii were shown to be effective antivitamins. Therefore, the antagonistic effect of vitamin B2 analogs in yeast cells is realized at the level of coenzyme forms.
Insights
Researchers studied riboflavin (RF) analogs for biological activity. Certain RF analogs act as antivitamins, inhibiting yeast growth by interfering with coenzyme forms.
Area of Science:
- Biochemistry
- Microbiology
- Medicinal Chemistry
Context:
- Riboflavin (RF), an essential vitamin, plays a crucial role in various metabolic processes.
- Understanding RF analogs is vital for developing potential therapeutic agents and studying metabolic pathways.
- Yeast, specifically Pichia guilliermondii MS1, serves as a model organism for evaluating biological activity due to its RF-dependent nature.
Purpose:
- To investigate the biological activity of 32 structural riboflavin analogs.
- To identify riboflavin analogs with antagonistic properties against yeast growth.
- To elucidate the mechanism of action for effective antivitamin analogs.
Summary:
- 32 riboflavin (RF) analogs were synthesized and tested for biological activity using an RF-dependent yeast mutant.
- Antagonistic properties were observed in D-ribityl derivatives with specific substitutions (CF3, Cl, H, NH2, N(CH3)2) at the methyl groups, showing inhibition indices from 0.52 to 10.8.
- Antiviral activity was dependent on structural features, including substitutions at positions 7, 8, 10, the isoalloxazine ring, and the D-ribityl side chain. Phosphorylation by RF kinase was crucial for activity.
Impact:
- Identified specific structural modifications in riboflavin analogs that confer antivitamin activity.
- Demonstrated that the antagonistic effect of these analogs in yeast is mediated at the coenzyme level.
- Provides a basis for designing novel riboflavin analogs with potential applications in medicine or as research tools.