1. Additional evidence was obtained that the nuclear oestradiol-17beta receptor is an acidic protein. Partial purification of the receptor protein was obtained by chromatography on hydroxyapatite and it contains protein-bound phosphate. 2. The nuclear ;5s' and cytoplasmic ;9.5s' and ;5s' receptors from uterus, dimethylbenzanthracene-induced mammary adenocarcinoma and kidney are precipitated together with bound oestradiol-17beta by protamine sulphate. This common property suggests that the nuclear and cytoplasmic receptors are related to each other. 3. The properties of two acidic protein fractions from both liver and dimethylbenzanthracene-induced mammary adenocarcinoma are described. Fraction 1 contains two major components and fraction 2 contains one component, as judged from polyacrylamide-gel electrophoresis. Fraction 2 contains RNA and both fractions contain protein-bound phosphate. 4. These fractions form insoluble complexes with calf thymus histone, protamine sulphate and poly-l-lysine. The formation of these complexes is markedly affected by ionic strength and pH. Ionization of both the in-amino group of lysine and carboxyl group are involved. RNA and DNA do not appear to be involved. The interaction is not affected by EDTA or 1mm-Na(+), -K(+), -Ca(2+), -Mg(2+) or -Mn(2+). Per unit weight, whole histone has 4-5 times as many binding sites for the acidic proteins as the latter have for the former. 5. No convincing evidence was obtained for DNA-acidic protein interaction, but, as judged from precipitation experiments, there was competition between DNA and acidic protein for histone. 6. Relatively large amounts of acidic protein partly relieved the histone inhibition of the template activity of DNA for Escherichia coli RNA polymerase (EC 2.7.7.6).

Adenocarcinoma↗

PubMed1969

A test to measure the immunosuppressive potency of antilymphocyte sera.

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Animals↗

PubMed1969

Specificity and evolutionary divergence of the antigenic structure of the polypeptide chain elongation factors.

Antisera have been prepared against two electrophoretically homogeneous "polypeptide chain elongation factors," T and G, from Escherichia coli. Inactivation and precipitation tests showed that these two fractions were antigenically distinct with no cross-reaction. The immune inactivation curve of G factor from E. coli was distinguishable from that of G factor from Pseudomonas fluorescens. Mammalian factors were not inhibited by antibody directed against the E. coli T and G factors. By Ouchterlony diffusion tests, the antisera also detected significant antigenic variability among different bacterial species. It is concluded that the factors have undergone considerable evolutionary divergence in their antigenic structure.

Antigens↗