The guanido group of arginine condenses with 1, Z-cyclohexanedione in alkaline aqueous medium to form a new a-amino acid. The product (1 ,2-cyclohexanedione-arginine) was shown by independent synthesis to be N5-(4-0x0-1,3diazaspiro[4.4]non 2 ylidene) L ornithine. At hydroxide concentrations of 0.2 N or higher, this was the principal product, and the reaction with free arginine and with the argi...

The existence of an alkali-labile bound form of niacin, different from other known derivatives of niacin, in cereal grains has already been established (l-6). The concentration of this substance was found to be the highest in the bran among the different parts of the grain (7). Krehl et al. (5, 6) concentrated it from wheat bran to a certain degree and considered from its solubility and dipolar...

Among the many biological reactions which have attracted attention during recent years, the one bearing the name of Abderhaldenl has been prominent. The simple nature of the underlying idea, that a circulating foreign protein induces in the blood a corresponding and specific defensive ferment which accomplishes its hydrolysis, combined with the obvious importance of its applications, has render...

In this study, a simple, fast, accurate and sensitive spectrophotometric method has been developed for the determination of tranexamic acid in bulk and pharmaceutical preparations. The method is based on the reaction of ninhydrin with the primary amino group of tranexamic acid in the basic medium at pH 8.0. The reaction produces a bluish-purple color which absorbs maximally at 565 nm. Beer's la...

In this paper the results concerning the synthesis of magnetite (Fe₃O₄) nanoparticles (NPs), their functionalization using silane derivatives, such as (3-Aminopropyl)triethoxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane (MPTMS), and their exhaustive morphological and physical characterization by field emission scanning electron microscopy (FE-SEM) with energy dispersion X-ray spectrome...

Various authors have reported methods for the colorimetric estimation of alpha-amino nitrogen with ninhydrin (Moore and Stein, 1948, 1954; Smith and Agiza, 1951 ; Troll and Cannan, 1953; Yemm and Cocking, 1955; Kalant, 1956; Rosen, 1957). Only Kalant has applied this method to the direct measurement of alpha-amino nitrogen in biological fluids; he reported on the determination of total alpha-am...

In a previous report (1) the isolation, toxicity and some chemical data concerning the lipopolysaccharide endotoxin of Neisseria gonorrhoeae was described. The present investigation includes the following: (a) an improved modification of lipopolysaccharide phosphoric acid ester preparation; (b) hydrolysis of lipopolysaccharide phosphoric acid ester and removal of fatty acids; (c) separation of ...

Two simple, rapid and green spectrophotometric methods are described for the determination of lisinopril medicines. The is based on reaction primary amino group with ninhydrin in aqueous medium (Method I) carboxylic copper (II) sulfate II). For both methods, optimal conditions were established. linear relationship was found between absorbance at λmax concentration drug range 40–60 µg/mL 0.592–2...