Induction of ferritin synthesis in vitro: problems of specificity inherent in the use of iron compounds.
The potential importance of heme as a translational regulator has been recognized for nearly 30 years. However, the ability to distinguish the specific regulatory effects of heme from the nonspecific effects has been hampered by its high reactivity and its tendency to generate reactive by-products in most systems. In this article we discuss some of the technical difficulties in studying the effects of iron salts and compounds, notably heme, in biochemical systems in vitro. Data are presented which show that the nonspecific inhibitory effects of heme on two restriction endonucleases can be eliminated by (a) including a redox buffer in the reaction mixture, and (b) maintaining a sufficiently high total protein concentration. Under these conditions, the specific effects of hemin on the ferritin repressor protein are still observed. A possible relationship between these observations and the status of 'free' heme in vivo is considered.
Lin
J J
JJ
Department of Biology, Washington University, St. Louis, Mo.
Walden
W E
WE
Thach
R E
RE
D015245:Deoxyribonuclease BamHI / Q000378:metabolism / Q000494:pharmacology; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism / Q000494:pharmacology; D005293:Ferritins / Q000096:biosynthesis*; D005786:Gene Expression Regulation; D006418:Heme / Q000378:metabolism / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism*; D035941:Iron Regulatory Protein 1; D035925:Iron-Regulatory Proteins; D016601:RNA-Binding Proteins / Q000378:metabolism*
D035925:Iron-Regulatory Proteins; D016601:RNA-Binding Proteins; D006418:Heme; D005293:Ferritins; D007501:Iron; D015245:Deoxyribonuclease BamHI; D015252:Deoxyribonucleases, Type II Site-Specific; C024400:GTYRAC-specific type II deoxyribonucleases; D035941:Iron Regulatory Protein 1