scholarly journals Plant leaf alanine: 2-oxoglutarate aminotransferase. Peroxisomal localization and identity with glutamate:glyoxylate aminotransferase

1981 ◽  
Vol 195 (1) ◽  
pp. 235-239 ◽  
Author(s):  
T Noguchi ◽  
S Hayashi
Keyword(s):  
Spinacia Oleracea ◽  
Soluble Fraction ◽  
Sucrose Density Gradient ◽  
Soluble Enzyme ◽  
Plant Leaves ◽  
Peroxisomal Enzyme ◽  
Enzyme Preparations ◽  
Predominant Form ◽  
Single Form ◽  
Alanine Aminotransferase Activity

The distribution of alanine:2-oxoglutarate aminotransferase (EC 2.6.1.2) in spinach (Spinacia oleracea) leaf homogenates was examined by centrifugation in a sucrose density gradient. About 55% of the total homogenate activity was localized in the peroxisomes and the remainder in the soluble fraction. The peroxisomes contained a single form of alanine:2-oxoglutarate aminotransferase, and the soluble fraction contained two forms of the enzyme. Both the peroxisomal enzyme and the soluble predominant form (about 90% of the total soluble activity) were co-purified with glutamate:glyoxylate aminotransferase to homogeneity; it had been reported to be present exclusively in the peroxisomes of plant leaves and to participate in the glycollate pathway in leaf photorespiration [Tolbert (1971) Annu. Rev. Plant Physiol. 22, 45-74]. The evidence indicates that alanine:2-oxoglutarate aminotransferase and glutamate:glyoxylate aminotransferase activities are associated with the same protein. The peroxisomal and soluble enzyme preparations had nearly identical properties, suggesting that the soluble predominant alanine aminotransferase activity is from broken peroxisomes and about 96% of the total homogenate activity is located in peroxisomes.

Re-Investigation of the Protein Structure of Coenzyme B12-Dependent Diol Dehydrase

1987 ◽  
Vol 42 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Katsuyuki Tanizawa ◽  
Nobuyoshi Nakajima ◽  
Tetsuo Toraya ◽  
Hidehiko Tanaka ◽  
Kenji Soda
Keyword(s):  
Protein Structure ◽  
Membrane Fraction ◽  
Enzyme Purification ◽  
Soluble Fraction ◽  
Proteolytic Cleavage ◽  
Subunit Structure ◽  
Coenzyme B12 ◽  
Enzyme Preparations ◽  
Protein Components ◽  
Limited Digestion

We have purified diol dehydrase, an adenosylcobalamin-dependent enzyme, from Klebsiella pneumoniae by two different procedures to re-investigate its protein structure; one including its extraction with detergent from the membrane fraction, and the other consisting of only chromato­graphic separations of the soluble fraction. The enzyme preparations obtained by these two methods were different in the subunit structure, but both are identical in molecular weight, and in enzymological and immunochemical properties. In addition, the enzyme preparation obtained from the membrane fraction dissociated reversibly into two dissimilar protein components (F and S) in the absence of substrate, as did the preparation from the soluble fraction. Although the subunit multiplicity of component S might be partly due to proteolytic cleavage during the enzyme purification as revealed by limited digestion with trypsin, component F is not a product of proteolytic cleavage of component S, but a primordial and essential constituent of the enzyme.

Conversion of Flavanone to Flavone, Dihydroflavonol and Flavonol with an Enzyme System from Cell Cultures of Parsley

1981 ◽  
Vol 36 (9-10) ◽  
pp. 742-750 ◽  
Author(s):  
L. Britsch ◽  
W. Heller ◽  
H. Grisebach
Keyword(s):  
Microsomal Fraction ◽  
Specific Activity ◽  
Enzyme System ◽  
High Specific Activity ◽  
Cell Suspension Cultures ◽  
Soluble Enzyme ◽  
Enzyme Preparations ◽  
Malonyl Coa ◽  
In Vitro Biosynthesis

Abstract Soluble enzyme preparations from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.) catalyse the conversion of flavanone to flavone, dihydroflavonol and flavonol. These reactions require 2-oxoglutarate, Fe2+ and ascorbate as cofactors. In the presence of these cofactors conversion of dihydroflavonol to flavonol was also observed. With this system in vitro biosynthesis of radioactive flavone, dihydroflavonol and flavonol from [2-14C]malonyl-CoA and 4-coumaroyl-CoA in good yield and with high specific activity is possible.We postulate that synthesis of flavone and flavonol from flavanone proceeds via 2-hydroxy-and 2,3-dihydroxyflavanone, respectively, with subsequent dehydration.The microsomal fraction of the parsley cells contains an NADPH-dependent flavanone 3'-hydroxylase.

Genetic and Biochemical Studies on the Conversion of Dihydroflavonols to Flavonols in Flowers of Petunia hybrida

1986 ◽  
Vol 41 (1-2) ◽  
pp. 179-186 ◽  
Author(s):  
G. Forkmann ◽  
P. de Vlaming ◽  
R. Spribille ◽  
H. Wiering ◽  
A. W. Schram
Keyword(s):  
Enzyme Activity ◽  
Petunia Hybrida ◽  
Soluble Enzyme ◽  
Flower Buds ◽  
Ph Optimum ◽  
Enzyme Preparations ◽  
Biochemical Studies ◽  
High Enzyme ◽  
Substantial Correlation ◽  
High Enzyme Activity

Abstract Soluble enzyme preparations from flower buds of Petunia hybrida catalyzed the conversion of dihydroflavonols to flavonols. Dihydrokaempferol and dihydroquercetin were readily converted to the respective flavonols, whereas dihydromyricetin was a poor substrate. The reaction required 2-oxoglutarate, ascorbate and Fe2+ as cofactors and had a pH optimum at about 6.5. In the presence of the dominant allele Fl, high enzyme activity for flavonol formation was found, whereas in enzyme preparations from flower buds of recessive genotypes (fl/fl) only low enzyme activity could be observed. A substantial correlation was found between enzyme activity for flavonol formation and the flavonol content of buds and flowers during development.

Conversion of Dihydroflavonols to Flavonols with Enzyme Extracts from Flower Buds of Matthiola incana R. Br.

1984 ◽  
Vol 39 (7-8) ◽  
pp. 714-719 ◽  
Author(s):  
R. Spribille ◽  
G. Forkmann
Keyword(s):  
Enzyme Activity ◽  
Flower Development ◽  
Rapid Decline ◽  
Soluble Enzyme ◽  
Flower Buds ◽  
Ph Optimum ◽  
Enzyme Preparations ◽  
Matthiola Incana ◽  
Substantial Correlation

Abstract Soluble enzyme preparations from flower buds of Matthiola incana catalysed the conversion of dihydrokaempferol to kaempferol and of dihydroquercetin to quercetin. The reaction required 2-oxoglutarate, ascorbate and Fe2+ as cofactors and had a pH-optimum at about 7.0. Highest enzyme activity was already present in the youngest buds followed by a rapid decline during bud and flower development. Furthermore, a substantial correlation was observed between the enzyme activity for flavonol formation and the flavonol content of the buds and flowers.

scholarly journals Purification of 3-phosphoglycerate kinase from diverse sources by affinity elution chromatography

1978 ◽  
Vol 175 (1) ◽  
pp. 311-319 ◽  
Author(s):  
T Fifis ◽  
R K Scopes
Keyword(s):  
Escherichia Coli ◽  
Kinetic Parameters ◽  
Phosphoglycerate Kinase ◽  
Bovine Liver ◽  
Detailed Comparison ◽  
Gradient Elution ◽  
Plant Leaves ◽  
Enzyme Preparations ◽  
Relative Electrophoretic Mobility ◽  
Elution Chromatography

1. Affinity elution chromatography was used to purify phosphoglycerate kinase from a variety of sources. The choice of buffer pH for the chromatography was made according to the relative electrophoretic mobility of the enzyme from the species concerned. 2. Outlines of the methods used to isolate the enzyme from over 20 sources are presented. The enzyme was purified from the muscle tissue of a variety of mammals, fish and birds, from liver of several animals, from yeast, Escherichia coli, and plant leaves. The more acidic varieties of the enzymes were purified by conventional gradient elution from ion-exchangers as affinity elution procedures were not applicable. 3. The structural and kinetic parameters investigated show that phosphoglycerate kinase is evolutionarily a highly conservative enzyme; there were few differences in properties regardless of source or function (glycolytic, gluconeogenic or photosynthetic). 4. A detailed comparison of the enzyme preparations purified from bovine muscle and bovine liver failed to detect any significant differences between them; the evidence indicates that they are genetically identical.

Cleavage of l-cystine by soluble enzyme preparations from Brassica species

1967 ◽  
Vol 120 (2) ◽  
pp. 371-378 ◽  
Author(s):  
Mendel Mazelis ◽  
Noreen Beimer ◽  
R.K. Creveling
Keyword(s):  
Brassica Species ◽  
Soluble Enzyme ◽  
Enzyme Preparations

scholarly journals A Computer-Vision-Based Approach for Nitrogen Content Estimation in Plant Leaves

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 766
Author(s):  
Tazeem Haider ◽  
Muhammad Shahid Farid ◽  
Rashid Mahmood ◽  
Areeba Ilyas ◽  
Muhammad Hassan Khan ◽  
...  
Keyword(s):  
Computer Vision ◽  
Visual Inspection ◽  
Spinacia Oleracea ◽  
Nitrogen Deficiency ◽  
Laboratory Analysis ◽  
Growth And Yield ◽  
Plant Leaves ◽  
Color Similarity ◽  
Highly Correlated ◽  
Different Color

Nitrogen is an essential nutrient element required for optimum crop growth and yield. If a specific amount of nitrogen is not applied to crops, their yield is affected. Estimation of nitrogen level in crops is momentous to decide the nitrogen fertilization in crops. The amount of nitrogen in crops is measured through different techniques, including visual inspection of leaf color and texture and by laboratory analysis of plant leaves. Laboratory analysis-based techniques are more accurate than visual inspection, but they are costly, time-consuming, and require skilled laboratorian and precise equipment. Therefore, computer-based systems are required to estimate the amount of nitrogen in field crops. In this paper, a computer vision-based solution is introduced to solve this problem as well as to help farmers by providing an easier, cheaper, and faster approach for measuring nitrogen deficiency in crops. The system takes an image of the crop leaf as input and estimates the amount of nitrogen in it. The image is captured by placing the leaf on a specially designed slate that contains the reference green and yellow colors for that crop. The proposed algorithm automatically extracts the leaf from the image and computes its color similarity with the reference colors. In particular, we define a green color value (GCV) index from this analysis, which serves as a nitrogen indicator. We also present an evaluation of different color distance models to find a model able to accurately capture the color differences. The performance of the proposed system is evaluated on a Spinacia oleracea dataset. The results of the proposed system and laboratory analysis are highly correlated, which shows the effectiveness of the proposed system.

scholarly journals Predicting soil water repellency by hydrophobic organic compounds and their vegetation origin

2015 ◽  
Vol 2 (1) ◽  
pp. 153-186
Author(s):  
J. Mao ◽  
K. G. J. Nierop ◽  
M. Rietkerk ◽  
S. C. Dekker
Keyword(s):  
Fatty Acid ◽  
Soil Water ◽  
Organic Compounds ◽  
Hydroxy Fatty Acid ◽  
Soluble Fraction ◽  
Water Repellency ◽  
Primary Role ◽  
Plant Leaves ◽  
Hydrophobic Organic Compounds ◽  
Soil Water Repellency

Abstract. It is widely accepted that soil water repellency (SWR) is mainly caused by plant-derived hydrophobic organic compounds in soils; such hydrophobic compounds are defined as SWR-markers. However, the detailed influence of SWR-markers on SWR is yet unclear and the knowledge of their original sources is still limited. The aims of this study are to select important SWR-markers to predict SWR based on their correlation with SWR and to determine their origin. In our study, sandy soils with different SWR were collected, along with their covering vegetation, i.e. plant leaves/needles and roots. A sequential extraction procedure was applied to the soils to obtain three organic fractions: DCM / MeOH soluble fraction (D), DCM / MeOH insoluble fraction of IPA / NH3 extract (AI) and DCM / MeOH soluble fraction of IPA / NH3 extract (AS), which were subdivided into ten dominant SWR-marker groups: (D) fatty acid, (D) alcohol, (D) alkane, (AI) fatty acid, (AI) alcohol, (AI) ω-hydroxy fatty acid, (AI) α, ω-dicarboxylic acid, (AS) fatty acid, (AS) alcohol and (AS) ω-hydroxy fatty acid. Waxes and biopolyesters of the vegetation were also sequentially extracted from plants. In short, the soils with higher SWR have significantly higher relative concentrations of (AS) alcohols. A number of indications suggest that (AS) alcohols are mainly derived from roots and most likely produced by microbial hydrolysis of biopolyesters/suberins. In addition, the strong correlation between the biomarkers of plant tissues and SWR-markers in soils suggests that it is more accurate to predict SWR of topsoils using ester-bound alcohols from roots, and to predict SWR of subsoils using root-derived ω-hydroxy fatty acids and α, ω-dicarboxylic acids. Our analysis indicates that plant roots have a primary role influencing SWR relative to plant leaves.

scholarly journals Characterization of a cytoskeletal matrix associated with myelin from rat brain

1989 ◽  
Vol 260 (3) ◽  
pp. 689-696 ◽  
Author(s):  
C S Gillespie ◽  
R Wilson ◽  
A Davidson ◽  
P J Brophy
Keyword(s):  
Rat Brain ◽  
Soluble Fraction ◽  
Gradient Centrifugation ◽  
Proteolipid Protein ◽  
Immunoblot Analysis ◽  
Sucrose Density Gradient ◽  
Insoluble Residue ◽  
Sucrose Density Gradient Centrifugation ◽  
Specific Proteins ◽  
Cytoskeletal Elements

Extraction of rat brain myelin in a buffer containing Triton X-100 yielded a soluble fraction and an insoluble residue that was enriched in cytoskeletal elements. Immunoblot analysis of the detergent-soluble fraction and the insoluble cytoskeletal residue showed that all of the tubulin and more than half of the actin were found within the cytoskeletal fraction. The distribution of myelin-specific proteins was also examined, and revealed that 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNPase) I and most of the myelin basic proteins (MBPs) were equally distributed between both fractions. By contrast, the large MBP (21.5 kDa) and CNPase II (50 kDa) were observed to partition almost entirely with the cytoskeletal fraction. Proteolipid protein was found predominantly in the detergent-soluble fraction, as was DM-20 protein. Analysis of the cytoskeletal fraction by sucrose-density-gradient centrifugation demonstrated that a distinct subset of lipids was tightly bound to the cytoskeletal protein residue. The cytoskeleton-associated lipid was considerably enriched in cerebroside and sphingomyelin by comparison with total myelin lipids. These results indicate that a cytoskeletal matrix is associated with multilamellar myelin, and suggest that this structure may play a fundamental role in myelinogenesis.

scholarly journals Development of glutamate:glyoxylate aminotransferase in the cotyledons of cucumber (Cucumis sativus) seedlings

1982 ◽  
Vol 201 (1) ◽  
pp. 209-214 ◽  
Author(s):  
T Noguchi ◽  
S Fujiwara
Keyword(s):  
Physical Properties ◽  
Cucumis Sativus ◽  
Aminotransferase Activity ◽  
Plant Leaves ◽  
Enzyme Preparations ◽  
Cucumber Seedlings

Glutamate:glyoxylate aminotransferase had been reported to be present exclusively in the peroxisomes of plant leaves and to participate in the glycollate pathway in leaf photorespiration (Tolbert (1971) Annu. Rev. Plant Physiol. 22, 45-74]. Glutamate:glyoxylate aminotransferase activity was already present in the etiolated cotyledons of cucumber (Cucumis sativus) seedlings, and increased during greening. The enzyme was present only in the cytosol of the etiolated cotyledons and appeared in the peroxisomes during greening. The enzyme was purified to homogeneity from the cytosol of the etiolated cotyledons and from the peroxisomes of the green cotyledons of cucumber seedlings. The two enzyme preparations had nearly identical enzymic and physical properties. On the basis of these findings, roles of glutamate:glyoxylate aminotransferase in the glycollate pathway in photorespiration, and the mechanism of its appearance in the peroxisomes during greening, are discussed.

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