Aspartate Aminotransferase Isozymes in Panicum miliaceum L, an NAD-Malic Enzyme-Type C4 Plant: Comparison of Enzymatic-Properties, Primary Structures, and Expression Patterns

1995 ◽  
Vol 318 (2) ◽  
pp. 295-306 ◽  
Author(s):  
M. Taniguchi ◽  
A. Kobe ◽  
M. Kato ◽  
T. Sugiyama
Keyword(s):  
Aspartate Aminotransferase ◽  
Malic Enzyme ◽  
Expression Patterns ◽  
Enzymatic Properties ◽  
Panicum Miliaceum ◽  
C4 Plant ◽  
Primary Structures

Structure of genes that encode isozymes of aspartate aminotransferase in Panicum miliaceum L., a C4 plant

1994 ◽  
Vol 26 (2) ◽  
pp. 723-734 ◽  
Author(s):  
Mitsutaka Taniguchi ◽  
Junji Mori ◽  
Tatsuo Sugiyama
Keyword(s):  
Aspartate Aminotransferase ◽  
Panicum Miliaceum ◽  
C4 Plant

scholarly journals Cloning and sequence analysis of cDNA encoding aspartate aminotransferase isozymes from Panicum miliaceum L., a C4 plant

1992 ◽  
Vol 204 (2) ◽  
pp. 611-620 ◽  
Author(s):  
Mitsutaka TANIGUCHI ◽  
Hiromichi SAWAKI ◽  
Hideo SASAKAWA ◽  
Toshiharu HASE ◽  
Tatsuo SUGIYAMA
Keyword(s):  
Sequence Analysis ◽  
Aspartate Aminotransferase ◽  
Panicum Miliaceum ◽  
C4 Plant

Phosphoenolpyruvate Carboxykinase in C4 Plants: Its Role and Regulation

1997 ◽  
Vol 24 (4) ◽  
pp. 459 ◽  
Author(s):  
Robert P. Walker ◽  
Richard M. Acheson ◽  
László I. Técsi ◽  
Richard C. Leegood
Keyword(s):  
Molecular Mass ◽  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
C4 Plants ◽  
Panicum Maximum ◽  
C4 Plant ◽  
Cam Plants ◽  
Crude Extracts ◽  
High Concentrations ◽  
Regulatory Properties

Some of the recent findings which revise our view of the role and regulation of phosphoenolpyruvate carboxykinase (PEPCK) in C4 plants are discussed. Evidence is presented that PEPCK is present at appreciable activities in the bundle-sheath of some NADP-malic enzyme-type C4 plants, such as maize, but it was not detectable in NAD-malic enzyme-type C4 plants. PEPCK is rapidly inactivated in crude extracts of leaves of the C4 plant, Panicum maximum. This inactivation could be prevented by high concentrations of dithiothreitol or by the inclusion of ADP or ATP, suggesting the involvement of thiols at the active site. PEPCK is also subject to rapid proteolysis in crude extracts of a range of C4 plants, resulting in cleavage to a smaller (62 kDa) form. This can be reduced by extraction at high pH and by the inclusion of SDS, but it means that intact PEPCK has never been purified from a C4 plant. The molecular mass of PEPCK varies considerably in C4 plants, unlike C3 and CAM plants in which it is usually 74 kDa. PEPCK is phosphorylated during darkness (and reversed by light) in some C4 plants with PEPCK of a larger molecular mass, such as Panicum maximum (71 kDa), but it was not phosphorylated in the PEPCK-type C4 plant, Sporobolus pyramidalis (69 kDa). The known regulatory properties of PEPCK are discussed in relation to its role in C4 photosynthesis, in particular its sensitivity to regulation by adenylates and by Mn2+.

Photosynthesis in Phosphoenolpyruvate Carboxykinase-Type C4 Species: Properties of Nad-Malic Enzyme From Urochloa panicoides

1987 ◽  
Vol 14 (5) ◽  
pp. 517 ◽  
Author(s):  
JN Burnell
Keyword(s):  
Malic Enzyme ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Bundle Sheath ◽  
Photosynthetic Pathway ◽  
C4 Plant ◽  
C4 Species ◽  
Absolute Requirement ◽  
Pep Carboxykinase ◽  
Fructose 1,6 Bisphosphate ◽  
Regulatory Properties

NAD-malic enzyme (EC 1.1.1.39) was purified from bundle sheath strands of Urochloa panicoides (a phosphoenolpyruvate carboxykinase-type C4 plant) and its kinetic and regulatory properties were investigated. The native enzyme has a molecular weight of about 470 000 and is an octomer composed of two slightly different monomers which occur in a 1 : 1 ratio. The enzyme has an absolute requirement for Mn2+, is stimulated by CoA, acetyl CoA, fructose 1,6-bisphosphate and SO42- and is inhibited by HCO3, oxaloacetate, 2-oxoglutarate and pyruvate. The enzyme is shown to be localised in the mito- chondria. The purified NAD-malic enzyme is unable to catalyse the carboxylation of pyruvate according to the reverse reaction. These findings are discussed in relation to the C4 photosynthetic pathway and its possible role in PEP carboxykinase-type C4 plants.

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