Comparison of Chorismate Mutase Isozyme Patterns in Selected Plants

Woodin, Terry S.; Nishioka, Leo; Hsu, Alice J.

doi:10.1104/pp.61.6.949

Cited by 15 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2A) which is in agreement with a previous report (3). Similar contradictory results were obtained for Nicotiana tabacum by Goers and Jensen (14) who argued that the third isoenzyme reported earlier (27) may prove to be an electrophoretic variant of one of the four allelic CM-1 cistrons of N. tabacum. Authors (26,27) presenting the evidence for three isoenzymes of chorismate mutase argued that the lack of a third chorismate mutase isozyme in some plants was due to CM-3 (the third isoenzyme) being highly unstable.…”

Section: Methodssupporting

confidence: 91%

See 1 more Smart Citation

Chorismate Mutase Isoenzymes from Selected Plants and Their Immunological Comparison with the Isoenzymes from Sorghum bicolor

Singh¹,

Lonergan²,

Conn³

1986

Plant Physiol.

View full text Add to dashboard Cite

The isoenzyme pattern of chorismate mutase (EC 5.4.99.5) was examined by diethylaminoethyl-cellulose chromatography in a wide variety of plants. All plants contained a regulated form of chorismate mutase (CM-I), and most contained an additional, unregulated form (CM-2). The regulatory properties of CM-I differed significantly between plants. Antisera prepared against CM-I and CM-2 from Sorghum bicolor were used to test immunological cross reaction of chorismate mutases from other plants. There was a high degree of similarity between chorismate mutase isoenzymes from Sorghum bicolor and Zea mays and some with Hordeum vulgare, but all other species studied were antigenically distinct from sorghum. No homology between the structure of CM-I and CM-2 was detected within any species.The shikimate pathway provides the precursors for the biosynthesis of the aromatic amino acids phenylalanine, tyrosine, and tryptophan in plants as well as in microorganisms (8,12,19 (15).In spite of the importance of chorismate mutase in phenylalanine and tyrosine biosynthesis, the information available in the literature is limited to a very few species. In this report, we present the partial purification, the regulatory properties and antigenic similarity to the sorghum enzyme of chorismate mutases from several species, differing in morphology (monocots and dicots) and physiology (C3, C4, and CAM). MATERIALS AND METHODSPlant Material. The plants used for this study were selected on the basis of their morphological and physiological characteristics. Green seedlings of Avena sativa (C3, monocot), Brassica oleracea (C3, dicot), Hordeum vulgare (C3, monocot), Pennisetum typhoides (C4, monocot), and Zea mays (C4, monocot) were grown by planting seeds in wet vermiculite in a growth chamber at 28°C under 12 h fluorescent illumination. Shoots from 6-to 7-d-old seedlings were used for the extraction of enzyme. Young, green leaves of Amaranthus hypochondriacus (C4, dicot), Hoya carnosa (CAM, dicot), Medicago sativa (C3, dicot), and Xerosicyos danguyi (CAM, dicot) were obtained from adult plants grown in a greenhouse and exposed to normal spring and summer daylengths. Young, green leaves from wild adult plants of Eschscholtzia californica (C3, dicot) were used. Spinacia oleracea (C3, dicot) leaves were obtained from a local supermarket.Enzyme Extraction. For the extraction of chorismate mutase, 20 to 25 g of shoots or leaf tissues were powdered in liquid N2 and extracted at 0 to 4°C with one volume of buffer A (100 mM Tris-HCl, pH 8.0, containing 1 mM tryptophan and 0.1% 2-mercaptoethanol). The extract was filtered through two layers of cheesecloth (grade 60) and centrifuged at 60,000g for 90 min in a Beckman model L ultracentrifuge. All subsequent purification steps were carried out at 0 to 4°C. Desalting. The centrifuged supernatant was loaded at 7 ml/min onto a bed of Sephadex G-25 (2.5 x 29.0 717 www.plantphysiol.org on April 1, 2019 -Published by Downloaded from

show abstract

Section: Methodssupporting

confidence: 91%

“…Reports from another laboratory (26,27) have indicated presence of three isoenzymes in a large number of plant species including three species examined in this work (A. sativa, M. sativa, and Z. mays). However, these findings have not been confirmed by any other laboratory.…”

Section: Methodsmentioning

confidence: 65%

Chorismate Mutase Isoenzymes from Selected Plants and Their Immunological Comparison with the Isoenzymes from Sorghum bicolor

Singh¹,

Lonergan²,

Conn³

1986

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Woodin and Nishioka published the first report of tryptophan sensitive isozymes (16,17). They resolved three forms of CM from several plant species.…”

Section: Resultsmentioning

confidence: 99%

Differential Activities of Chorismate Mutase Isozymes in Tubers and Leaves of Solanum tuberosum L.

Kuroki

Conn²

1989

Plant Physiol.

View full text Add to dashboard Cite

Chromatography on DEAE cellulose equilibrated with Pipes buffer resolved three forms of chorismate mutase (CM) from tubers and leaves of Solanum tuberosum: CM-IA and CM-1B were activated by tryptophan and inhibited by phenylalanine and tyrosine; CM-2 was unaffected by these aromatic amino acids. When compared to freshly excised discs, 3 day old tuber discs demonstrated a 4.5-fold increase in CM-1 activity following wounding. By contrast, CM-2 activity levels were not affected by this treatment. In aged tuber discs the CM-1:CM-2 activity ratio was 9:1. However, in green leaves the CM-1:CM-2 activity ratio was 1:4 suggesting organ specific regulation for the expression of these isozymes. The CM-I isozymes isolated from both tubers and leaves shared similar native molecular weight values of 55,000, Km values of 40 to 56 micromolar, and inhibition by phenylalanine (110-145 micromolar concentrations required for 50% inhibition) and tyrosine (50-70 micromolar concentrations required for 50% inhibition). The resolution of CM-1 into two forms occurred only in the presence of Pipes buffer. When this buffer was replaced with Aces, Bes, imidazole or Tris, only a single peak of CM-1 activity was observed. In these buffers CM-2 eluted as a shoulder on the CM-1 peak. Analytical isoelectric focusing of the CM-1 fraction followed by assay of the gel yielded only one form of CM-1 with an isoelectric point of 5.0. Gel filtration studies with Pipes buffer yielded molecular weights of 60,000 for both CM-1A and CM-lB indicating these forms are not the result of aggregation. The two forms of CM-1 may be artifacts generated by Pipes buffer.Chorismate mutase (EC 5.4.99.5) isozymes have been well resolved by chromatography on DEAE cellulose in a number of plants (5,6,14,15). Isozyme CM2-I has been shown to be activated by tryptophan and inhibited by phenylalanine and tyrosine, whereas CM-2 is not regulated by these aromatic amino acids. However, in other studies, only CM-1 activity could be detected following anion exchange chromatography (9, 15). In a previous investigation we detected only CM-1 activity in tubers of Solanum tuberosum following DEAE cellulose chromatography in citrate-phosphate buffer (9). Recent studies with parsley cell cultures (KF McCue, EE Conn, unpublished data) indicated that CM-1 and CM-2 may coelute on DEAE cellulose. This suggested that a similar phenom- enon might be occurring in the potato system. Utilizing DEAE cellulose equilibrated with Pipes buffer, Morris et al. (12) have recently detected CM-2 in potato tubers. We also report the resolution of CM-1 and CM-2 isozymes from tubers and green leaves of S. tuberosum. The data presented in this study revealed that ofthe five buffers employed, complete resolution of tuber CM isozymes on DEAE cellulose occurred only with Pipes buffer.The separation of CM-I and CM-2 by chromatography on DEAE cellulose allowed us to observe the effects of wounding and organogenesis on the expression of these shikimate pathway enzymes. Similar studies have been reported f...

show abstract

“…It is known that chorismate mutase (CM) catalyzes the conversion of chorismate to prephenate and this, in turn, will participate in the biosynthesis of the aromatic amino acids phenylalanine and tyrosine, precursors of secondary metabolites such as lignin, alkaloids and cinnamic acid (Mobley et al, 1999;Anterola and Lewis, 2002;Tzin and Galili, 2010;Westfall et al, 2014). In Arabidopsis, three chorismate mutase isoforms (CM1, CM2 and CM3) were identified (Woodin et al, 1978); CM1 and CM3 are located in the plastids, while CM2 is found in the cytosol (Eberhard et al, 1996;Mobley et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Research Article Early down-regulation of chorismate mutase 2 gene expression in a sugarcane cultivar tolerant to <i>Xanthomonas</i> <i>albilineans</i> infection

Rosa-Santos¹,

Nogueira²,

Paz³

et al. 2019

Genet. Mol. Res.

View full text Add to dashboard Cite

Xanthomonas albilineans causes leaf scald disease, one of the most economically important diseases of sugarcane. Leaf scald is a systemic and vascular disease that can severely reduce productivity. The best and primary method of leaf scald control is the use of tolerant cultivars. Knowing that cell wall lignification is a plant defense mechanism and that chorismate mutase is relevant in this process, we analyzed the expression pattern of the chorismate mutase 2 (SoCM2) gene in two contrasting sugarcane cultivars by RT-qPCR. A similar pattern of downregulation for the SoCM2 gene was observed in both cultivars; however, after 72h, the tolerant cultivar (RB867515) showed repression of the SoCM2 gene, while for the susceptible cultivar (SP78-4467), SoCM2 gene downregulation occurred only after 144h. Here we propose that early T.M. repression of the SoCM2 gene is responsible for tolerance to X. albilineans infection in the sugarcane cultivar RB867515.

show abstract

Comparison of Chorismate Mutase Isozyme Patterns in Selected Plants

Cited by 15 publications

References 25 publications

Chorismate Mutase Isoenzymes from Selected Plants and Their Immunological Comparison with the Isoenzymes from Sorghum bicolor

Chorismate Mutase Isoenzymes from Selected Plants and Their Immunological Comparison with the Isoenzymes from Sorghum bicolor

Differential Activities of Chorismate Mutase Isozymes in Tubers and Leaves of Solanum tuberosum L.

Research Article Early down-regulation of chorismate mutase 2 gene expression in a sugarcane cultivar tolerant to <i>Xanthomonas</i> <i>albilineans</i> infection

Contact Info

Product

Resources

About