Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three different molecular forms, isoforms, of the major virus-inducible anionic peroxidase (PRX) of cucumber (Cucumis sativus L.) were purified to homogeneity from crude extracts of hypersensitively reacting cotyledons and subjected to proteolysis with five exogenous endoproteinases. The PRX isoforms were fully resistant to degradation by trypsin and chymotrypsin even though at a prolonged incubation. Partial proteolysis with pepsin yielded peptides which were similar in size and serological properties. When papain was used, the peptides released from PRX1 isoform differed both in size and number but not serologically from the peptides released from isoforms PRX2 and PRX3 confirming similar primary structure of polypeptide chains. PRX3 was the only substrate giving a peptide map after incubation with protease K. Under experimental conditions used in this work, PRXI and PRX2 were degraded completely with protease K. These results indicate that PRX1, PRX2, and PRX3 contain similar antigenic determinants and indicate very similar but not identical primary structures. Several practical implications of the present study are also mentioned.
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PMID:Differential sensitivity of purified isoforms of cucumber anionic virus-inducible peroxidase to exogenous proteases. 1075 32

Three forms of anionic peroxidase (PRX) from hypersensitively reacting cucumber cotyledons were purified to homogeneity and different methods were used to analyze the nature of their carbohydrate chains. Immunoblot analysis with betaF1 antiserum showed that all three forms are highly glycosylated and contain asparagine N-linked glycans commonly found in other plant glycoproteins. Mobility shift analysis showed that chemical deglycosylation converted PRXs 1, 2 and 3 to the same-sized (35 K) products. Enzymatic deglycosylation with alpha-mannosidase converted PRX1 and PRX2 to immunoreactive products migrating in mobility shift polyacrylamide gels at the positions of PRX2 and PRX3, respectively. PRX3 treated with alpha-mannosidase yielded a product with Mr similar to that obtained with the chemical deglycosylation. Cleavage of the PRXs 1, 2 and 3 by formic acid at the Asp-Pro site resulted in peptide maps and the putative glycopeptide(s) were recognized using betaF1 antiserum. Only one glycopeptide was observed for each of the forms. Lectin-affinity blot analysis using biotin-conjugated lectins suggested that virus-inducible PRX contains complex-type N-glycosyl carbohydrate chain(s). These results indicate that heterogeneity of cucumber virus-inducible PRX is not caused mainly by differences in the terminal alpha-linked mannose residues.
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PMID:The glycosylation status and the role of carbohydrate moieties in the heterogeneity of cucumber anionic virus-inducible peroxidase. 1125 69

The development of soybeans tolerant to the soybean aphid [Aphis glycines Matsumura (Hemiptera: Aphididae)] remains unexplored. The objectives of this research were to determine the susceptibility of two high-yielding soybean [Glycine max (L.) Merrill (Fabales: Fabaceae)] genotypes involved in a breeding platform to develop aphid-tolerant recombinant inbred lines (RILs); characterize the peroxidase activity and relative expression of peroxidase transcripts in the parents of RILs; and identify an assay to phenotype aphid-tolerant RILs. Enzyme kinetic assays documented the total peroxidase activity for tolerant (KS4202), susceptible (SD76R), and two high-yielding (U09-105007 and U11-611112) soybeans during two vegetative stages (V1 and V3) at three sampling days (D4, D6, and D8 after aphid introduction). Enzyme kinetic assays showed that V3 infested tolerant and U11-611112 plants had significantly higher peroxidase activity than their respective control plants at D4, and infested tolerant plants were also higher than control plants at D6. There were no apparent trends when comparing the expression of peroxidase-specific transcripts in the absence of aphids (basal levels) in both V1 and V3. Relative expression analyses of two peroxidase transcripts (PRX52 and PRX2) performed to compare differences among the soybean genotypes indicated that, despite basal levels being similar for the treatments analyzed, tolerant soybeans had a tendency for a higher expression of PRX52 in the presence of aphids. Based on the different patterns observed and the feasibility of analyses performed in this study, enzyme kinetics using V3 infested plants may be a marker for screening RILs in a breeding program targeting the development of aphid-tolerant soybeans.
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PMID:Characterization and Identification of Methods for Phenotyping Soybean Populations With Tolerance to the Soybean Aphid (Hemiptera: Aphididae). 2998 24