| 摘要 |
A diagnostic composition for L-amino acids in body fluids comprises a bibulous carrier having impregnated therein (a) an enzyme having L-amino acid oxidative activity, (b) an enzyme or other substance having peroxidative activity (c) an indicator forming or changing colour in the presence of peroxide and (d) an activator for said enzyme (a). Specified enzymes having L-amino acid oxidative activity are L-amino oxidates from Crotalus adamanteus, dried snake venom from Agkistrodom p. Piscivorus, rat kidneys, turkey liver, microorganisms and moulds. Specified substances having peroxidative activity are horseradish and fig latex peroxidases, urohemin, blood and molybdate/iodide. Specified indicators are tincture of guaiac, o-tolidine, 2:5-diaminotoluene, 2HCl, 3:3/svdimethoxybenzidine, p-phenetidine.HCl, and pyrogallolsulphonephthalein. Specified activators are:- chlorides, flavin adenine dinucleotide, flavin mononucleotide and acriflavin. The composition may also comprise a buffer preferably tris(hydroxymethyl)aminomethane), a stabiliser (bovine albumin, gelatin, oxidised polysaccharides), a wetting agent (bis (2-ethylhexyl) sodium sulphosuccinate) and a thickening agent (algin, polyvinyl alcohol, starch, gum arabic and high m.w. polyethylene glycol). In the preferred form, a test strip impregnated with the composition comprises a zone at one end free from the composition or having a divalent metal (Ba, Mg, Ca, Cd, Sr, Pb) chloride impregnated therein. When said end is contacted with a sample containing enzyme inhibiting ions, e.g. sulphate, phosphate or benzoate ions, these are removed, and release enzyme-activating chloride ions, before the sample reaches the composition. Details of the preparation of test strips are provided. It is also stated that in making a test, the sample may be aspirated into a medicine dropper containing an ion exchange resin whereby on expelling a drop on to an impregnated paper, interfering ions are removed, and in further embodiments acheiving the same ends, (a) impregnated cellulose fibres may be placed above an ion exchange column and (b) cellulosic ion exchange fibres are employed both as inhibiting ion remover and as carrier.
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