The conversion of citrulline to arginine (transimination) by tissue slices and homogenates.
نویسندگان
چکیده
The conversion of citrullme to arginine by a transimination reaction involving glutamic acid and metabolically related compounds has been reported to take place in kidney slices by Borsook and Dubnoff (1). These authors found that liver slices did not catalyze the reaction and further that the breakdown of cell structure of kidney tissue, such as by homogenization, resulted in a loss of activity. In the course of an investigation on the mechanism of urea synthesis in liver, some evidence for the transimination reaction was obtained in homogenates fortified with adenosine triphosphate (ATP), magnesium ions, and cytochrome c. These findings, which are reported in a separate publication (2), led to a study of the transimination reaction in kidney and other tissue homogenates. Experiments reported in this paper deal with (1) the conditions l;equired for demonstrating the transimination reaction in tissue homogenates and (2) the relative rates of this reaction in slices ati homogenates of kidney and liver.
منابع مشابه
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 کاملBiosynthesis of urea; enzymatic mechanism of arginine synthesis from citrulline.
In urea synthesis, according to the Krebs-Henseleit ornithine cycle (l), the transfer of nitrogen to citrulline to form arginine (Step II) was thought to occur from NH$. It was not until Cohen and Hayano (2) succeeded in demonstrating rapid arginine synthesis in liver homogenates from glutamic acid and citrulline that the transfer from an amino acid rather than from NH, was recognized as a main...
متن کاملBiosynthesis of urea; arginine synthesis from citrulline in liver homogenates.
A preceding paper described the characteristics of the isolated enzyme system, prepared from ox liver acetone powder, which catalyzes the conversion of citrulline and aspartic acid to arginine and malic acid. It was shown that the fundamental requirements for arginine synthesis from citrulline are aspartic acid, Mg++, and adenosine triphosphate (ATP), the latter as a reactant in substrate conce...
متن کاملThe enzymatic steps in urea synthesis.
lnvestigations on the synthesis of arginine from citrulline (Step II of the Krebs-Henseleit urea cycle) and citrulline from ornithine (Step I) by rat liver homogenates have been reported previously (l-3). The study of the latter reaction was made possible by the apparently critical magnesium ion concentration required for the function of the liver transimination (citrulline to arginine) system....
متن کاملThe mechanism of arginine synthesis from citrulline in kidney.
The synthesis of arginine from citrulline by the mammalian kidney was first demonstrated by Borsook and Dubnoff (1) using tissue slices. The successful use of kidney homogenates was later. reported by Cohen and Hayano (2). As with arginine formation in liver, the studies with respiring tissue did not clearly reveal t’he nature of the reactions involved. It was of interest to see whether the enz...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 166 1 شماره
صفحات -
تاریخ انتشار 1946