Carboxylierungsreaktionen in Agaricus bisporus III. Pyruvat und Phosphoenolpyruvat als CO2-Acceptoren
✍ Scribed by Bachofen, Reinhard ;Rast, Dora
- Book ID
- 104764306
- Publisher
- Springer-Verlag
- Year
- 1968
- Weight
- 932 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0003-9276
No coin nor oath required. For personal study only.
✦ Synopsis
Cell-free extracts from Agaricus bisporus catalyze the synthesis of malate, fumarate and aspartate from pyruvate and CO~ in the presence of Mn ~+, and from phosphoenolpyruvate and CO~ with Mg ~+ (partially replaceable by Max+).
The carboxylatioa of pyruvate is highly stimulated by ATP and NADPtt s, but is not affected by CoA-esters. The reaction is inhibited by pCMB, oxalate and avidia.
The carboxylation of phosphoenolpyruvate is stimulated by ADP, but not by IDP and GDP.
From eofactor-requirement and inhibitor studies it is concluded, that there are two enzymes, pyruvateearboxylase and malic enzyme, which catalyze the carboxylation of pyruvate. Phosphoenolpyruvate earboxykinase is responsible for the COs-fixation into oxaloaeetate.
The significance of these three enzymes is discussed in connection with the nutrition of the fungus from its natural growth substrate and with the regulation of glycogenesis and the citric acid cycle.