Roger L. Munier

Incorporation d'analogues structuraux d'aminoacides dans les protéines bactériennes au cours de leur synthèse in vivo

Abstract The structural analogues of amino acids, p -fluorophenylalanine,β-2-thielalanine, and norleucine are incorporated into the bacterial proteins during the phase of linear growth of E. coli . 4- and 5-methyltryptophan which inhibit the growth of E. coli and the synthesis of active β-galactosidase do not seem to be incorporated into the bacterial proteins. 6-Methyltryptophan and p -chlorophenylalanine which have no effect on the growth of E. coli and on the biosynthesis of β-galactosidase are not incorporated into the proteins of E. coli . p -Fluorophenylalanine and β-2-thienylalanine on the one hand and norleucine on the other hand are incorporated into the proteins instead of phenylalanine and methionine, respectively. The whole of the reported results bring the authors to believe that the structural analogues which can be incorporated into bacterial proteins during the phase of linear growth do not act by inhibiting the biosynthesis of the proteins but by bringing about the synthesis of proteins which are abnormal by their structure and their activity.

Effets des analogues structuraux d'aminoacids sur la croissance, la synthèse de protéines et la synthèse d'enzymes chez Escherichia coli

1. 1. Numerous analogues of amino acids, when added to cultures of E. coli in the exponential phase, cause a transformation of exponential into linear growth. Concurrently, one or several enzymes cease to be synthesized in an active form. It is suggested that these arrests of synthesis are the cause of the linear growth. 2. 2. However, the proteins continue to be synthesized during the period of linear growth as is shown by the incorporation of radioactive sulphur and of radioactive valine and by the appearance of all the marked amino acids in the protein fraction after cultivation with radioactive glucose as the only source of carbon.

Chromatographie à deux dimensions des dinitrophénylamonoacides éthérosolubles et chromato-électrophorèse des DNP-aminoacides hydro-acido-solubles, en couche mince de pourde de cellulose

Resume Des methodes efficaces de separation chromatographique des DNP-aminoacides sur couche mince (250 μ) de poudre de cellulose sans liant sont decrites. Dans les conditions operatoires utilisees, il est possible de separer, sous forme de taches extremement bien definies tous les DNP-aminoacids du groupe de ethero-solubles et des hydro-acido-solubles. Sur plaque 20 × 20 (ou 30) cm, la quantite optimum de chaque DNP-aminoacide pouvant etre mise en oeuvre est de 3 a 7 mμmoles.

New strategy for the characterization of amino acids by thin-layer electrophoresis and thin-layer chromatography using acidic mobile phases.

Abstract Rapid, easy, and reliable identification procedures for the common amino acids (1- to 10-nmol amounts) based upon an association of low-voltage electrophoresis (1.04 m formic acid) and chromatography (propanol or isopropanol/formic acid/water, 75/5/20, v/v) on a cellulose thin layer and the use of a well-adapted mixture of structural analogs of amino acids are described. Applications of these procedures are also given.