Charles Hurwitz

The interactions between nucleic acids and polyamines. II. Protonation constants and 13C-NMR chemical shift assignments of spermidine, spermine, and homologs.

Abstract Macroscopic protonation constants have been determined by pulentiometric titration for spermidine, spermine and for the four pulyamines. 3,5-Spd, 4,4-Spd, 4,3,4-Spm and 4,4,4-Spm. which are homologs of spermidine and spermine. A method for calculation of microscopic protonation constants of polyamines based on data for mono- and diamines gives results for spermidine that agree well with the experimental macroscopic protonation constants and the protonation sequence of Kimberly and Goldstein. 13 C-NMR spectra of spermidine, spermine and six homologs have been obtained and used to assign specific resonances, correcting some ambiguity in the assignments for spermidine and some errors in the assignments for spermine.

Role of ribosome recycling in uptake of dihydrostreptomycin by sensitive and resistant Escherichia coli.

Exposure of streptomycin-resistant cells to puromycin results in uptake of dihydrostreptomycin comparable to that found with streptomycin-sensitive cells. This finding indicates that the enhanced phase of uptake, previously reported only in sensitive cells, may result from an increase in internal binding sites, presumably run-off ribosomes. The increased uptake of dihydrostreptomycin resulting from exposure to puromycin is greatest in both sensitive and resistant cells at concentrations below 100 microgram/ml. At 100 microgram/ml, exposure to puromycin in vivo results in significant, but not complete, polysome degradation and inhibition of protein synthesis. At 500 microgram/ml, where polysome degradation is complete in less than 2 min and where growth and protein synthesis are inhibited more than 90%, uptake of dihydrostreptomycin by both sensitive and resistant cells is inhibited. Puromycin has no effect on binding of dihydrostreptomycin to 70-S monosomes, as measured by equilibrium dialysis. The increased uptake of dihydrostreptomycin by resistant cells resulting from exposure to puromycin has no effect on viability. Addition of N-ethylmaleimide immediately and completely inhibits the puromycin-induced uptake of dihydrostreptomycin even when added after substantial polysome degradation has occurred.

Interrelationship between magnesium and polyaxines in a pseudomanad lacking spermidine

Abstract We have verified the report that Pseudomonas (Kim) contains no spermidine, but have found that this strain contains another polyamine, 2-hydroxyputrescine, previously unidentified in bacteria. As in Escherichia coli the concentration of magnesium in the S-100 fraction is the same as the extracellular concentration. Unlike Escherichia coli both ribosome-bound putrescine and ribosome-bound hydroxyputrescine vary inversely with extracellular concentration of magnesium, but the behavior of bound hydroxyputrescine in Pseudomonas (Kim) resembles that of bound spermidine in Escherichia coli .

The interactions between nucleic acids and polyamines. III. Microscopic protonation constants of spermidine.

Changes in the NMR chemical shifts of protons adjacent to the nitrogen atoms of Spermidine which are undergoing protonation have been measured by two-dimensional heteronuclear coupled NMR. Data thus obtained measure the dependence of the state of protonation of individual nitrogens on the pH, and permit calculation of the microprotonation constants of Spermidine and the concentrations of all of the variously protonated Spermidine species present at any pH.

Isolation and purification of a C1q-anti C1q precipitin ring enhancing protein from sera of patients with rheumatoid arthritis

Abstract We have isolated and purified to apparent homogeneity a serum protein which appears to be a biological marker for active rheumatoid arthritis. The protein has been found in the sera in all 44 active rheumatoid arthritis patients thus far studied and is absent from, or present in undetected amounts, in sera from normal subjects or from patients with other arthritides. The protein has a molecular weight of 135,000 daltons, an isoelectric pH of 5.1–5.3, and it enhances the size of the C1q-anti C1q ring.

Interference by polyamines in the measurement of magnesium ion at physiological pH with the divalent cation-selective electrode.

Abstract The liquid ion exchange divalent cation-selective electrode responds in a non-Nernstian manner to a number of protonated amines and polyamines of biochemical interest. This electrode response is characterized for a number of amines and the interference of protonated amines in measurement of magnesium ions at physiological pH is discussed.

Serum levels of RHP and of unbound C1q in rheumatoid arthritis and systemic lupus erythematosus

RHP is a recently described serum protein which inhibits a number of physiologic functions of Clq unbound to Clr2×Cls2. In this report we show that sera from patients with rheumatoid arthritis contained elevated levels of RHP and of unbound Clq. Sera from patients with systemic lupus erythematosus contained normal levels of RHP and were characterized by deficits of Clq required to form Cl from existing levels of Clr and Cls.

Two-dimensional n.m.r. investigation of the protonation sequence in spermidine

Proton–carbon-13 two-dimensional correlation n.m.r spectroscopy resolves the four protons adjacent to the nitrogen atoms of spermidine and permits determination of the protonation sequence.