Umanoff H, Russell C S, Cosloy S D
Department of Biochemistry, City College of New York, City University of New York 10031.
J Bacteriol. 1988 Oct;170(10):4969-71. doi: 10.1128/jb.170.10.4969-4971.1988.
A hemin-permeable hemB mutant had no 5-aminolevulinate dehydratase (ALA D) and extremely low porphobilinogen deaminase (PBG D) activity. When the structural gene for hemB was introduced into this strain on a single-copy plasmid, both activities were observed. When the mutant was grown on PBG, normal PBG D activity was observed. Moreover, a hemA mutant had little or no PBG D activity unless it was grown on ALA or PBG. Neither hemin nor PBG affected the level of PBG D protein produced from in vitro transcription and translation of a plasmid harboring the hemC gene as an insert. We conclude that, in Escherichia coli, PBG availability controls the activity of PBG D at some posttranscriptional level.
一个对血红素通透的hemB突变体没有5-氨基酮戊酸脱水酶（ALA D），并且胆色素原脱氨酶（PBG D）活性极低。当hemB的结构基因通过单拷贝质粒导入该菌株时，两种活性均被观察到。当该突变体在胆色素原上生长时，观察到正常的PBG D活性。此外，一个hemA突变体除非在5-氨基酮戊酸或胆色素原上生长，否则几乎没有或没有PBG D活性。血红素和胆色素原均不影响从以hemC基因为插入片段的质粒进行体外转录和翻译所产生的PBG D蛋白水平。我们得出结论，在大肠杆菌中，胆色素原的可利用性在转录后水平控制PBG D的活性。
