Relaxation method for constrained minimization of the maximum function

Translated from Issledovaniya po Prikladnoi Matematike, Kazan', No. 14, pp. 25–34, 1987.     

On the mechanism of C ⇄ N migration of alkoxycarbonyl groups in reactions of pyridinium ylides with isocyanates

New examples of reversible C N migrations of alkoxycarbonyl groups, which occur in the reactions of pyridinium and 3-(diethylcarbamoyl)pyridinium ylides, viz., derivatives of dimethyl and diethyl malonates, with aryl isocyanates were studied. The mechanism of migration of the methoxycarbonyl group from the carbon atom to the nitrogen atom was considered on the basis of quantum-chemical calculations. The product of the primary attack of the isocyanate group by pyridinium ylide was established to be rearranged with low potential barriers to form carbamate without formation of cyclic intermediate compounds.     

Modified oxidation of (+)-3-carene by potassium permanganate

The oxidation of (+)-3-carene under the conditions of phase-transfer catalysis has been studied. It has been shown that when the reaction is performed in acetic acid the keto acids (IIa) and (IIIa) and (–)-3-hydroxycaran-4-one (IV) are formed.Institute of Organic Chemistry, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 338–340, May–August, 1992.     

Arginylation and methylation double up to regulate nuclear proteins and nuclear architecture in vivo

Protein arginylation and arginine methylation are two posttranslational modifications of emerging importance that involve Arg residues and their modifications. To test a hypothesis that posttranslationally added arginines can be methylated, we used high-precision mass spectrometry and metabolic labeling to find whether posttranslationally added arginines can serve as methylation sites. We identified?a number of proteins in?vivo, on which posttranslationally added Arg have undergone mono- and dimethylation. This double modification predominantly affects the chromatin-containing nuclear fraction and likely plays an important regulatory role in chromatin-associated proteins. Moreover, inhibition of arginylation and Arg methylation results in?a significant reduction of the nucleus size in cultured cells, suggesting changes in chromatin compaction and nuclear architecture. Our findings suggest?a functional link between protein regulation by arginylation and methylation that affects nuclear structure in?vivo.