Mary L. Petermann

The subunits and structural ribonucleic acids of Jensen sarcoma ribosomes

Abstract 1. 1. The molecular weights of the Jensen sarcoma ribosome and its large subunit, calculated from their sedimentation and diffusion coefficients, are 4.3·106 and 2.7·106 respectively. The molecular weights of the ribosomal RNAs, calculated from their sedimentation coefficients and intrinsic viscosities, are 1.64·106 and 0.67·106 respectively. Thus these ribosomes appear to dissociate into two subunits, of approximately two thirds and one third, each containing one strand of structural RNA that makes up half its mass. 2. The large subunit exists in a variety of states whose sedimentation coefficients decrease from 57 S to 30 S as cations are removed. These changes have been attributed to changes in conformation. 3. The small subunit has been found in two forms: 33 S when magnesium is present and 29 S in its absence.

A cryoglobulin of high sedimentation rate (macroglobulin) from human serum

Abstract A cryoglobulin of high sedimentation rate has been described. In the whole serum, or after partial purification, this protein existed in several different forms, and showed association or dissociation with variation in temperature, ionic strength, pH, or protein concentration. After more extensive purification this property was lost.

Ultracentrifugal studies of the process of thyroglobulin hydrolysis.

Abstract 1. 1. A saline extract of thyroid glands from radioiodide-injected rats was purified by a single phosphate precipitation and incubated at 37 °C. and pH 5.2 for 35 hr. in the presence of cysteine. Following dialysis and tenfold concentration, the digest was studied in the ultracentrifuge, in the analytical and partition cells. Radioactivity data from the latter were compared with data from dialysis, salting out, chromatography, and electrophoresis. An unincubated control was similarly studied. 2. 2. This method of hydrolyzing thyroglobulin produces nondialyzable intermediates that sediment slowly in the ultracentrifuge, as well as other fragments with faster rates. At a time when amino acids accounted for a third of the radioactivity, the intermediates constituted a third to a half. 3. 3. In the ultracentrifugal pattern of crude rat thyroid extracts, thyroglobulin constitutes 51% of the total sedimenting material. A faster boundary contains 9%, and three slower boundaries comprise 6, 7, and 27%, respectively. The sedimentation coefficient of rat thyroglobulin is 18.0 S , for a 0.59% solution.

Plasma proteins in bacterial infections.

For the sake of completeness, it seems necessary that someone in this monograph review the effects of bacterial infection on the plasma proteins. I have therefore undertaken this task. Although I have never worked directly in this field, I have tried to keep up with it, since many of the protein abnormalities seen in patients with cancer must be attributed to the presence of lowgrade infections. I shall discuss changes in the plasma proteins: first, in acute bacterial infections, and second, in chronic infections, and then I shall review the literature on the C-reactive protein.

The binding properties of rat-liver ribosomes: Complexes formed with cytochrome c

Abstract 1. 1. To understand more fully the nature of electrostatic binding to ribosomes and to gain greater insight into the effect such binding may have on the structure of these particles, the binding of the oxidized monomer form of cytochrome c to 80-S rat-liver ribosomes and to the 47-S ribosomal subunit was investigated. 2. 2. The binding to 80-S ribosomes and to the larger ribosomal subunit, 47 S, was found to be similar. The binding constants decreased rapidly from 0.16·10 6 almost to zero as the ionic strength increased from 0.022 to 0.124. The number of binding sites on the 80-S monomers also decreased with increasing ionic strength perhaps as a result of an increase in compactness at the higher salt concentrations. 3. 3. In solutions of 0.04 ionic strength there was a slight but continuous decrease in binding strengths as the pH increased from 6.5 to 9.5. Secondary binding, only one-tenth as strong, but also electrostatic in nature, became evident above pH 7.6. At neutral pH, 115 molecules of cytochrome were bound per 80-S ribosome and 93 molecules per 47-S subunit. 4. 4. The form taken by the complex was a function of pH, ionic strength, temperature, and the ratio of the concentrations of the reactants.