| Literature DB >> 4354855 |
P A Srere, B Mattiasson, K Mosbach.
Abstract
An immobilized three-enzyme system, malate dehydrogenase (EC 1.1.1.37)-citrate synthase (EC 4.1.3.7)-lactate dehydrogenase (EC 1.1.1.27), was investigated as a model for the rate of oxalacetate production and utilization in mitochondria. Lactate dehydrogenase is included to mimic the NADH-utilizing system of mitochondria. This three-enzyme system was immobilized in three different ways (1) on Sephadex G-50 (surface coupling), (2) on Sepharose 4B (internal-external coupling), and (3) entrapped in polycrylamide gel. The rate of citrate production from malate, NAD(+), and acetyl CoA was determined continuously in a flow system. Up to about 100% rate enhancements were observed when the immobilized system was compared to identical systems of free enzyme. An even more pronounced increase of rate of up to about 400% compared to the soluble system was measured after addition of pyruvate (to reoxidize formed NADH). These results are interpreted in relation to microenvironmental changes of oxalacetate production and the possible organization of enzymes of the Krebs cycle.Entities:
Mesh：
Substances：
Year: 1973 PMID： 4354855 PMCID： PMC427050 DOI： 10.1073/pnas.70.9.2534
Source DB: PubMed Journal: Proc Natl Acad Sci U S A ISSN： 0027-8424 Impact factor: 11.205