Determination of the Kinetic and Chemical Mechanism of Malic Enzyme Using (2R,3R)-erythro-Fluoromalate as a Slow Alternate Substrate†

Biochemistry ◽  
1998 ◽  
Vol 37 (51) ◽  
pp. 18026-18031 ◽  
Author(s):  
Jeffrey L. Urbauer ◽  
Debra E. Bradshaw ◽  
W. W. Cleland
Keyword(s):  
Malic Enzyme ◽  
Chemical Mechanism ◽  
Alternate Substrate

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

Determination of the chemical mechanism of glutamate dehydrogenase from pH studies

Biochemistry ◽  
1980 ◽  
Vol 19 (11) ◽  
pp. 2328-2333 ◽  
Author(s):  
James E. Rife ◽  
W. W. Cleland
Keyword(s):  
Glutamate Dehydrogenase ◽  
Chemical Mechanism

Computations by Means of Macroscopic Chemical Kinetics

2006 ◽  
Author(s):  
John Ross ◽  
Igor Schreiber ◽  
Marcel O. Vlad
Keyword(s):  
Chemical Kinetics ◽  
Reaction Mechanisms ◽  
Parallel Machines ◽  
Electronic Device ◽  
Chemical Mechanism ◽  
Chemical Systems ◽  
Universal Turing Machine ◽  
Sequential Machines ◽  
Logic Functions

The topic of this chapter may seem like a digression from methods and approaches to reaction mechanisms, but it is not; it is an introduction to it. We worked on both topics for some time and there is a basic connection. Think of an electronic device and ask: how are the logic functions of this device determined? Electronic inputs (voltages and currents) are applied and outputs are measured. A truth table is constructed and from this table the logic functions of the device, and at times some of its components, may be inferred. The device is not subjected to the approach toward a chemical mechanism described in the previous chapter, of taking the device apart and testing its simplest components. (That may have to be done sometimes but is to be avoided if possible.) Can such an approach be applicable to chemical systems? We show this to be the case by discussing the implementation of logic and computational devices, both sequential machines such as a universal Turing machine (hand computers, laptops) and parallel machines, by means of macroscopic kinetics; by giving a brief comparison with neural networks; by showing the presence of such devices in chemical and biochemical reaction systems; and by presenting some confirming experiments. The next step is clear: if macroscopic chemical kinetics can carry out these electronic functions, then there are likely to be new approaches possible for the determination of complex reaction mechanisms, analogs of such determinations for electronic components. The discussion in the remainder of this chapter is devoted to illustrations of these topics; it can be skipped, except the last paragraph, without loss of continuity with chapter 5 and beyond. A neuron is either on or off depending on the signals it has received. A chemical neuron is a similar device.

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

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 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.

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