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

Authenticity of speciality sugars – Determination of carbohydrate source and geographical origin of invert sugar syrup and burnt sugar syrup

2017 ◽  
pp. 87-91
Author(s):  
Andreas G. Degenhardt ◽  
Elke Jansen ◽  
Timo, J. Koch
Keyword(s):  
Geographical Origin ◽  
Hydrological Cycle ◽  
Isotope Ratios ◽  
Saccharum Officinarum ◽  
Invert Sugar ◽  
C4 Plants ◽  
Yeast Fermentation ◽  
Carbohydrate Source ◽  
Sugar Syrup

Modern instrumental analytical methods for the determination of 13C/12C ratios are established to differentiate between metabolic products of C3 and C4 plants. Differentiation and identification of sucrose from pure beet (Beta vulgaris) and pure cane (Saccharum officinarum) are possible without doubt. Influenced by the worldwide hydrological cycle the determination of the isotope ratios of 2H/1H and 18O/16O as well as their variations provide information about geographical origin. Using samples of selected crystal cane sugar (CCS) with known origin, invert sugar syrups (ISS) as well as burnt sugar syrups (BSS) produced therefrom, the authenticity was determined. The speciality sugars ISS and BSS which were made from CCS could be identified as carbohydrates of C4 plants by using 13C/12C Isotope-Ratio Mass Spectrometry (IRMS). In combination with yeast fermentation of ISS and sugar separation from BSS and fermentation into ethanol as well as knowledge about production water, the C2-H/O isotope ratios of ethanol can theoretically determine the geographical origin of the sugars.

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+.

Possible involvement of phosphoenolpyruvate carboxylase and NAD-malic enzyme in response to drought stress. A case study: a succulent nature of the C4-NAD-ME type desert plant, Salsola lanata (Chenopodiaceae)

2017 ◽  
Vol 44 (12) ◽  
pp. 1219
Author(s):  
Zhibin Wen ◽  
Mingli Zhang
Keyword(s):  
Enzyme Activity ◽  
Drought Stress ◽  
Phosphoenolpyruvate Carboxylase ◽  
Malic Enzyme ◽  
C4 Plants ◽  
Leaf Water Content ◽  
Transcriptional Level ◽  
Desert Plant ◽  
Severe Stress ◽  
Real Time Quantitative Pcr

The co-ordination between the primary carboxylating enzyme phosphoenolpyruvate carboxylase (PEPC) and the further decarboxylating enzymes is crucial to the efficiency of the CO2-concentrating mechanism in C4 plants, and investigations on more types of C4 plants are needed to fully understand their adaptation mechanisms. In this study we investigated the effect of drought on carboxylating enzyme PEPC, and the further decarboxylating NAD-malic enzyme (NAD-ME) of Salsola lanata Pall. (Chenopodiaceae) – an annual succulent C4-NAD-ME subtype desert plant. We investigated enzyme activity at the transcriptional level with real-time quantitative PCR and at the translational level by immunochemical methods, and compared S. lanata with other forms of studied C4 plants under drought stress. Results showed that only severe stress limited PEPC enzyme activity (at pH 8.0) of S. lanata significantly. Considering that PEPC enzyme activity (at pH 8.0) was not significantly affected by phosphorylation, the decrease of PEPC enzyme activity (at pH 8.0) of S. lanata under severe stress may be related with decreased PEPC mRNA. The suggestion of increased phosphorylation of the PEPC enzyme in plants under moderate stress was supported by the ratio of PEPC enzyme activity at pH 7.3/8.0, as PEPC enzyme is inhibited by L-malate and the evidence of the 50% inhibiting concentration of L-malate. NAD-ME activity decreased significantly under moderate and severe stress, and coincided with a change of leaf water content rather than the amount of α-NAD-ME mRNA and protein. Leaf dehydration may cause the decrease of NAD-ME activity under water stress. Compared with other C4 plants, the activities of PEPC and NAD-ME of S. lanata under drought stress showed distinct features.

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

Quantum Yields of Photosystem II Electron Transport and Carbon Dioxide Fixation in C4 Plants

1990 ◽  
Vol 17 (5) ◽  
pp. 579 ◽  
Author(s):  
JP Krall ◽  
GE Edwards
Keyword(s):  
Carbon Dioxide ◽  
Electron Transport ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Malic Enzyme ◽  
Co2 Fixation ◽  
C4 Plants ◽  
Quantum Yields ◽  
Ps Ii ◽  
Co2 Concentrations

The quantum yields of non-cyclic electron transport from photosystem II (determined from chlorophyll a fluorescence) and carbon dioxide assimilation were measured in vivo in representative species of the three subgroups of C4 plants (NADP-malic enzyme, NAD-malic enzyme and PEP-carboxykinase) over a series of intercellular CO2 concentrations (CI) at both 21% and 2% O2. The CO2 assimilation rate was independent of O2 concentration over the entire range of Ci (up to 500 μbar) in all three C4 subgroups. The quantum yield of PS II electron transport was similar, or only slightly greater, in 21% v. 2% O2 at all Ci values. In contrast, in the C3 species wheat there was a large O2 dependent increase in PS II quantum yield at low CO2, which reflects a high level of photorespiration. In the C4 plants, the relationship of the quantum yield of PS II electron transport to the quantum yield of CO2 fixation is linear suggesting that photochemical use of energy absorbed by PS II is tightly linked to CO2 fixation in C4 plants. This relationship is nearly identical in all three subgroups and may allow estimates of photosynthetic rates of C4 plants based on measurements of PS II photochemical efficiency. The results suggest that in C4 plants both the photoreduction of O2 and photorespiration are low, even at very limiting CO2 concentrations.

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

NADP-Malic Enzyme: Immunolocalization in Different Tissues of C3 and C4 Plants

1995 ◽  
pp. 4217-4220
Author(s):  
María F. Drincovich ◽  
Verónica G. Maurino ◽  
Paula Casati ◽  
Carlos S. Andreo ◽  
Maurice Ku ◽  
...  
Keyword(s):  
Malic Enzyme ◽  
C4 Plants ◽  
C3 And C4 Plants ◽  
Different Tissues
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