No abstract

A rapid biochemical method for the determination of arginine decarboxylase (EC 4.1.1.19) activity has been developed for use in the routine clinical microbiology laboratory and correlated with similar procedures for ornithine and lysine decarboxylase (EC 4.1.1.18) systems. It is based on the detection of agmatine, the amine end product formed during growth on a synthetic medium containing arginine as the key amino acid. A modified diacetyl reagent is used to detect this amine after a differential butanol extraction of the cultures. This procedure can be used to detect this amine after a 1to 4-hr incubation period (with the use of an initial concentrated inoculum) or with an overnight culture. Thus, both an indirect measurement based on the alkalinization of the medium and a lengthy incubation period were avoided. Parameters for optimal enzyme activity and the pertinent enzyme systems involved in arginine and agmatine catabolism are discussed in detail.

This paper presents an adaptation of two methods into a single rapid and sensitive micro-quantitative and/or -qualitative procedure for use in the routine laboratory analyses of guanidino compounds. Agmatine can be quantitatively or qualitatively detected in the presence of arginine or creatine following a differential extraction with an alkaline -butanol solution. 80-85% of the agmatine is removed from an aqueous solution by this procedure. The agmatine is quickly visualized (within 3 min) by the addition of a modified diacetyl reagent to the butanol layer. As little as 5-10 pg/ml of agmatine can be detected. Differential extraction of several other guanidino and related compounds is discussed. In addition, the same reagent can be used to quantitate agmatine, arginine, creatine, and other guanidino-containing compounds over a range of 2-90 #¿g/ml. Time concentration curves are also presented.Agmatine, the amine formed by decarboxylation of arginine, is usually determined in biological systems either by the production of C02 (I), a color change in an indicator (2), or fluorometric analysis (3). Sakaguchi's reagent (4, J), diacetyl (6-5), and phenanthrequinone ( 9) have also been used to detect guanidino-containing compounds (10).This paper presents a rapid and sensitive micromethod for the qualitative and quantitative determination of agmatine, arginine, and several other guanidino-containing compounds. In combination with a modified differential procedure, agmatine can be determined in the presence of arginine.A simplified diacetyl reagent quickly allows the visualization of these compounds on either a qualitative or quantitative basis. EXPERIMENTALReagents and Equipment. All chemicals were reagent grade unless otherwise specified and the solvents were spectro quality. Glass distilled water was used. Solutions of 1naphthol and diacetyl (2,3-butanedione) were stored in dark (amber) glass bottles in the cold. Pre-coated Silica Gel

A rapid biochemical method for the determination of ornithine and lysine decarboxylase (EC 4.1.1.18) activity has been developed for use in the routine clinical laboratory. It is based on the detection of the amine end product produced in response to the single key amino acid added to a synthetic medium. A modified ninhydrin reagent is used to detect the amine after a chloroform extraction. This procedure can be used with a 1- to 4-hr incubation period (utilizing an initial concentrated inoculum) or with an overnight culture. Thus, measurements based on the alkalinization of the medium after a lengthy incubation period are avoided. Optimal parameters for enzyme activity are discussed.

A rapid biochemical method for the determination of arginine decarboxylase (EC 4.1.1.19) activity has been developed for use in the routine clinical microbiology laboratory and correlated with similar procedures for ornithine and lysine decarboxylase (EC 4.1.1.18) systems. It is based on the detection of agmatine, the amine end product formed during growth on a synthetic medium containing arginine as the key amino acid. A modified diacetyl reagent is used to detect this amine after a differential butanol extraction of the cultures. This procedure can be used to detect this amine after a 1- to 4-hr incubation period (with the use of an initial concentrated inoculum) or with an overnight culture. Thus, both an indirect measurement based on the alkalinization of the medium and a lengthy incubation period were avoided. Parameters for optimal enzyme activity and the pertinent enzyme systems involved in arginine and agmatine catabolism are discussed in detail.