Heller K
Can J Microbiol. 1978 Apr;24(4):467-72.
A non-competitive inhibition of binding of cAMP to bovine protein kinase by ochratoxin A (OTA) is shown. Preliminary evidence of a protein kinase in Streptococcus faecalis is presented. The cAMP stimulation of this kinase is also inhibited by OTA. At the lowest OTA concentrations, RNA and protein synthesis are inhibited in S. faecalis. The inhibition of RNA synthesis is secondary, as in the presence of chloramphenicol no inhibition occurs for 10 min after the addition of OTA. The synthesis but not the induction of beta-P-galactosidase is inhibited by OTA. The polysomes of S. faecalis are stabilized after addition of OTA, showing an inhibition of peptide elongation. The model of action of OTA in bacteria is discussed and it is concluded that inhibition of protein synthesis is the process which might be closest to the primary target of OTA.
研究表明，赭曲霉毒素A（OTA）对环磷酸腺苷（cAMP）与牛蛋白激酶的结合具有非竞争性抑制作用。文中给出了粪肠球菌中蛋白激酶的初步证据。该激酶的cAMP刺激作用也受到OTA的抑制。在最低OTA浓度下，粪肠球菌中的RNA和蛋白质合成受到抑制。RNA合成的抑制是继发性的，因为在添加OTA后10分钟内，若存在氯霉素则不会发生抑制作用。OTA抑制β-半乳糖苷酶的合成，但不抑制其诱导。添加OTA后，粪肠球菌的多核糖体得以稳定，表明肽链延伸受到抑制。文中讨论了OTA在细菌中的作用模式，并得出结论：蛋白质合成的抑制可能是最接近OTA主要靶点的过程。
