Lockhart & Abraham (1956) found that two compounds which appeared to be aspartyl-lysine and aspartyl(isoleucyl)-lysine respectively were formed when bacitracin A was hydrolysed with 11 Nhydrochloric acid at 800. The aspartic acid residue in these compounds had the L-configuration and was linked to the e-amino group of L-lysine. However, both compounds carried a net positive charge at pH 7 and t...

Two purified isozymes of protein carboxyl methyltransferase from bovine brain catalyze the substoichiometric transfer of methyl groups in vitro from S-adenosyl-L-[methyl-3H]methionine to several erythrocyte membrane proteins, which include bands 2.1, 3, and 4.1, as well as several integral membrane polypeptides. D-Aspartic acid beta-[3H]methyl ester has been isolated from proteolytic digests of...

The active components of the RNAi are 21 nucleotides long dsRNAs containing a 2 nucleotide overhang at the 3' end, carrying 5'-phosphate and 3'-hydroxyl groups (siRNAs). Structural analysis revealed that the siRNA is functionally bound at both ends to RISC. Terminal modifications are considered with interest as the introduction of chemical moieties interferes with the 3' overhang recognition by...

Three different serine proteinase inhibitors were isolated from rat serum and purified to apparent homogeneity. One of the inhibitors appears to be homologous to a1-proteinase inhibitor isolated from man and other species, but the other two, designated rat proteinase inhibitor I and rat proteinase inhibitor II, seem to have no human counterpart. ac-Proteinase inhibitor (Mr 55000) inhibits tryps...

A mutation of yeast pai1 has been isolated which leads to altered regulation of proteinase A inhibitor activity. Under conditions of derepression, this mutant as compared with wild type has a 70% reduction in proteinase A inhibitor activity, but no change in the activities of proteinase A or B. The growth of strains carrying the pai1 mutation is sensitive to temperature and pH. The altered phys...

1. The isolation, characterization and properties of two by-products in the preparation of 2-acetamido-3,4,6-tri-O- acetyl-2-deoxy-beta-d-glucopyranosylamine are described. They are bis(2-acetamido-2-deoxy-d-glucopyranosyl)amines. 2. An independent synthesis of the bis-glycopyranosylamines is reported and conditions are given for their preparation in high yield. 3. Further improvements are give...

Microcin C (McC), a peptide-nucleotide antibiotic, targets aspartyl-tRNA synthetase. By analyzing a random transposon library, we identified Escherichia coli mutants resistant to McC. Transposon insertions were localized to a single locus, yejABEF, which encodes components of a putative inner membrane ABC transporter. Analysis of site-specific mutants established that all four components of the...

A protein inhibitor of the Ca2+-dependent proteinase has been purified from bovine cardiac muscle by using the following steps in succession: salting out 17,600 X gmax supernatants from muscle homogenates in 50 mM Tris acetate, pH 7.5, 4 mM EDTA between 25 and 65% ammonium sulfate saturation; eluting between 25 and 120 mM KCl from a DEAE-cellulose column at pH 7.5; salting out between 30 and 60...

Thermal epimerization is the key to changing the endo-to-exo ratio of the diastereomeric bornyl and fenchyl Grignard reagents from 67:33 to 96:4 and from 20:80 to 80:20, respectively.