Synthesis of pyrimidine derivatives of amino acids using pig liver esterase and pancreas lipase.

The parent methyl ester of the N-1 substituted 5-chloropyrimidinone is hydrolysed by pig liver esterase to the corresponding carboxylic acid. The acid chloride was made with PCl5 in toluene, and coupling with benzyl and methyl esters of selected L-amino acids to the corresponding amides was done in dichloromethane in the presence of triethylamine. The benzyl and methyl ester protecting groups were hydrolysed with pancreas lipase or esterase in a pH-stat to yield the corresponding carboxylic acids.

The phosphate groups of the high mobility group like protein P1 strengthens its affinity for DNA.

PCA soluble proteins isolated from rat liver and proliferating HeLa interphase cells were subjected to chromatography on columns containing immobilized s.s and d.s.

On the expression of HMG I protein in quiescent and proliferating human T lymphocytes.

The results demonstrate that the HMG I protein is expressed in human quiescent T lymphocytes and hence is not dependent upon proliferation or neoplastic transformation. Furthermore it has been found that the HMG I/histone H1 ratio increase about two-fold after activation with phytohemagglutinin and was about the same as in a number of proliferating human leukemia lymphoma T-cell lines.

High-mobility-group proteins P1, I and Y as substrates of the M-phase-specific p34cdc2/cyclincdc13 kinase.

All dividing cells entering the M phase of the cell cycle undergo the transient activation of an M-phase-specific histone H1 kinase which was recently shown to be constituted of at least two subunits, p34cdc2 and cyclincdc13. The DNA-binding high-mobility-group (HMG) proteins 1, 2, 14, 17, I, Y and an HMG-like protein, P1, were investigated as potential substrates of H1 kinase. Among these HMG proteins, P1 and HMG I and Y are excellent substrates of the M-phase-specific kinase obtained from both meiotic starfish oocytes and mitotic sea urchin eggs.

The metaphase specific phosphorylation of HMG I.

In vivo labelling of HeLa cells arrested in metaphase with [32P]-phosphate and in vitro phosphorylation of HMG I with the partially purified growth associated H1 kinase was used to study metaphase specific phosphorylation of HMG I. It was found that threonine 53 and 78 became phosphorylated. These amino acids are embedded in respectively the sequence PTPKR and TPGRK which are similar to the sequences phosphorylated by the growth associated H1 kinase.