Morris D R, Hansen M T
J Bacteriol. 1973 Nov;116(2):588-92. doi: 10.1128/jb.116.2.588-592.1973.
The rates of elongation of beta-galactosidase and its messenger ribonucleic acid (RNA) were estimated in a polyamine-deficient mutant of Escherichia coli through an analysis of the kinetics of enzyme induction. The chain growth of beta-galactosidase was calculated from the time required after the appearance of an amino terminal fragment of 60 amino acids (auto-alpha) until completed enzyme began to accumulate. The elongation rate of beta-galactosidase messenger RNA was estimated from the time after induction at which streptolydigen-resistant, enzyme-forming capacity first appeared. Upon polyamine starvation, the rate of polypeptide elongation slowed from 17 to 10 amino acids per s and the messenger RNA elongation rate decreased from 47 to 30 nucleotides per s. These reductions in polymerization rates were proportional to the decrease in cellular growth rate produced by polyamine starvation. It was concluded that, although it is quite unlikely that polyamine levels are involved in regulation of cell growth, they may be acting as cofactors in the synthesis of RNA or protein, or both.
通过对酶诱导动力学的分析，估算了大肠杆菌多胺缺陷型突变体中β-半乳糖苷酶及其信使核糖核酸（RNA）的延伸速率。β-半乳糖苷酶的链生长是根据60个氨基酸的氨基末端片段（自身α片段）出现后到完整酶开始积累所需的时间来计算的。β-半乳糖苷酶信使RNA的延伸速率是根据诱导后首次出现抗链溶菌素、具有酶形成能力的时间来估算的。在多胺饥饿时，多肽延伸速率从每秒17个氨基酸减慢到每秒10个氨基酸，信使RNA延伸速率从每秒47个核苷酸降低到每秒30个核苷酸。这些聚合速率的降低与多胺饥饿导致的细胞生长速率下降成正比。得出的结论是，尽管多胺水平参与细胞生长调节的可能性很小，但它们可能作为RNA或蛋白质合成或两者合成中的辅助因子发挥作用。
