ChemkjaIBasis of the CarbamidodiacetylMicromethodfor Estima ’ tionof Urea , Citrulline , andCarbamylDerivatives

نویسنده

  • Catherine Vakirtzi-Lemonias
چکیده

The chemical pathway of the carbamidodiacetyl colorimetric assay was investigated. The experimental variables that were studied include reaction temperature, heating time, and the ratio of the mineral acid mixture to the reactants. Evidence is presented establishing the involvement of either 7or 8-methyl, or 7,8.d imethyltetrahyd roimidazo(4,5-d)imidazole-2,5-d iones as chromogens, all three being equally acceptable.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Study of carbon dioxide fixation in the synthesis of citrulline.

The ornithine + citrulline -+ arginine cycle of urea synthesis originally proposed by Krebs and Henseleit (1) has had increasing experimental support (2-10). The position of citrulline in the cycle, however, has been questioned (11). With the advent of the successful separation of the two over-all enzymatic steps, ornithine -+ citrulline and citrulline -+ arginine (lo), from the intact cellular...

متن کامل

Manipulation of citrulline availability in humans.

To determine whether circulating citrulline can be manipulated in vivo in humans, and, if so, whether citrulline availability affects the levels of related amino acids, nitric oxide, urinary citrulline, and urea nitrogen, 10 healthy volunteers were studied on 3 separate days: 1) under baseline conditions; 2) after a 24-h treatment with phenylbutyrate (0.36 g.kg(-1).day(-1)), a glutamine "trappi...

متن کامل

Sub-micromolar concentrations of extramitochondrial Ca2+ stimulate the rate of citrulline synthesis by rat liver mitochondria.

1. In the presence of physiological concentrations of Na+ and Mg2+, the rate of citrulline synthesis by isolated rat liver mitochondria respiring on a range of substrates was stimulated by up to 60% when the extramitochondrial Ca2+ concentration was raised from 130 pM to 770 nM. 2. Our findings suggest that hormonal stimulation of the urea cycle may be mediated by Ca2+.

متن کامل

Urea synthesis by liver homogenates.

The synthesis of citrulline from ornithine and arginine from citrulline has heretofore been associated only with intact liver cells. In the course of studies on the mechanism of the conversion of citrulline to a&nine, a highly active system was found in liver homogenate capable of forming urea in the presence of glutamic acid, adenosine triphosphate (ATP), cytochrome c, an oxygen atmosphere, an...

متن کامل

Regulation of urea and citrulline synthesis under physiological conditions.

Information on the regulation of urea synthesis in vivo was obtained by examining the relationship between ureagenesis in vivo, citrulline synthesis in vitro, and two factors currently hypothesized to exert short-term regulation of this pathway: the liver mitochondrial content of N-acetylglutamate (NAG) and substrate availability. Rats meal-fed for 4 h every day (4-20 schedule) or for 8 h every...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2004