scholarly journals Conceptual Error in Determination of NAD+-Malic Enzyme in Extracts Containing NAD+-Malic Dehydrogenase

1980 ◽  
Vol 65 (6) ◽  
pp. 1136-1138 ◽  
Author(s):  
William H. Outlaw ◽  
Jill Manchester
Keyword(s):  
Malic Enzyme ◽  
Malic Dehydrogenase

Determination of the Chemical Mechanism of Malic Enzyme by Isotope Effects†

Biochemistry ◽  
1997 ◽  
Vol 36 (5) ◽  
pp. 1141-1147 ◽  
Author(s):  
William A. Edens ◽  
Jeffrey L. Urbauer ◽  
W. W. Cleland
Keyword(s):  
Malic Enzyme ◽  
Isotope Effects ◽  
Chemical Mechanism

scholarly journals Determination of NAD Malic Enzyme in Leaves of C4 Plants

1982 ◽  
Vol 69 (2) ◽  
pp. 483-491 ◽  
Author(s):  
Marshall D. Hatch ◽  
Mikio Tsuzuki ◽  
Gerald E. Edwards
Keyword(s):  
Malic Enzyme ◽  
C4 Plants

Determination of the rate-limiting steps for malic enzyme by the use of isotope effects and other kinetic studies

Biochemistry ◽  
1977 ◽  
Vol 16 (4) ◽  
pp. 571-576 ◽  
Author(s):  
Michael I. Schimerlik ◽  
C. E. Grimshaw ◽  
W. W. Cleland
Keyword(s):  
Malic Enzyme ◽  
Isotope Effects ◽  
Kinetic Studies ◽  
Rate Limiting

The Role of Sodium in the Conversion of Pyruvate to Phosphoenolpyruvate in Mesophyll Chloroplasts of C4 Plants

1996 ◽  
Vol 23 (2) ◽  
pp. 171 ◽  
Author(s):  
PF Brownell ◽  
LM Bielig
Keyword(s):  
Oxygen Evolution ◽  
Malic Enzyme ◽  
Small Samples ◽  
Panicum Miliaceum ◽  
Tight Coupling ◽  
Irreversible Damage ◽  
C4 Species ◽  
The Hill

PEP formation from pyruvate was determined in mesophyll chloroplasts mechanically isolated from sodium-deficient and sodium-replete plants of the NADP malic enzyme-type C4 species, Kochia trichophylla. An extremely sensitive method for estimating PEP was developed which permitted determination of picomole quantities of PEP in small samples taken sequentially from the mesophyll chloroplast suspension concurrently with observations on oxygen evolution. It was shown that PEP formation requires light and depends upon the intactness of the chloroplasts. The rate of formation of PEP from pyruvate increased in the presence of the Hill reagent, oxaloacetate, thus indicating its dependence on non-cyclic photophosphorylation for the supply of ATP required in the conversion of pyruvate to PEP. The optimum inorganic phosphate concentration for PEP formation was approximately 16 mM. The rates of oxygen evolution and PEP formation were equivalent at concentrations of pyruvate up to 20 mM, suggesting tight coupling between electron transport and phosphorylation. In both Kochia trichophylla and the NAD malic enzyme-type, Panicum miliaceum, the rates of PEP formation were greater in the mesophyll chloroplasts from sodium-replete than from sodium-deficient plants. Chloroplasts resuspended in 'sodium-free'media containing less than 30 μM (0.7 ppm) sodium showed reduced rates of PEP formation compared with chloroplasts resuspended in media to which 1.0 mM (23 ppm) sodium had been added. Both media contained 10 mM 'sodium-free' KCI. These results indicate that sodium ions may be required to maintain the functional integrity of the mesophyll chloroplasts and that irreversible damage is sustained when sodium is absent during their isolation.

Determination of dissociation constants for enzyme-reactant complexes for NAD-malic enzyme by modulation of the thiol inactivation rate

Biochemistry ◽  
1984 ◽  
Vol 23 (23) ◽  
pp. 5454-5459 ◽  
Author(s):  
Dennis M. Kiick ◽  
Benja L. Allen ◽  
Jagannatha G. S. Rao ◽  
Ben G. Harris ◽  
Paul F. Cook
Keyword(s):  
Malic Enzyme ◽  
Dissociation Constants ◽  
Inactivation Rate

A putative pathway of glyconeogenesis in skeletal muscle

1981 ◽  
Vol 1 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Bhanu R. Odedra ◽  
T. Norman Palmer
Keyword(s):  
Skeletal Muscle ◽  
Malic Enzyme ◽  
Pyruvate Carboxylase ◽  
Phosphoenolpyruvate Carboxykinase ◽  
De Novo ◽  
Glycogen Biosynthesis ◽  
Glycogen Sparing ◽  
Specific Inhibitors

Evidence is presented in support of a pathway in skeletal muscle of glyconeogenesis (glycogen biosynthesis de novo) from L-glutamate and related amino acids involving the enzyme phosphoenolpyruvate carboxykinase (PEP CK). In the rat hemidiaphragm in vitro, not only did L-[U-14C]glutamate exert a glycogen-sparing action, but14C-label was incorporated into glycogen. The incorporation is thought not to be simply via label randomization and was decreased by factors that increased glycolysis or pyruvate oxidation. 3-Mercaptopicolinate and amino-oxyacetate, specific inhibitors of PEP CK and aminotransferase-type enzymes, respectively, decreased14C-incorporation from L-[U-14C]glutamate into glycogen. No quantitative determination of apparent glyconeogenic flux was made, and it remains to be established whether glyconeogenesis via PEP CK and/or via PEP CK coupled with 'malic' enzyme (or pyruvate carboxylase) is functionally important in skeletal muscle.

Sign in / Sign up

Export Citation Format

Share Document