scholarly journals Preliminary characterization of peroxidase isozymes isolated from two flax genotrophs

1977 ◽  
Vol 55 (11) ◽  
pp. 1465-1473 ◽  
Author(s):  
M. A. Fieldes ◽  
C. L. Deal ◽  
H. Tyson
Keyword(s):  
Molecular Weight ◽  
Oxidase Activity ◽  
Indoleacetic Acid ◽  
Relative Mobility ◽  
Fresh Weight ◽  
Iaa Oxidase ◽  
Peroxidase Isozymes ◽  
Flax Genotrophs ◽  
Very High

Four peroxidase (EC 1.11.1.7) isozymes were isolated from each of two flax genotrophs. All four isozymes were glycoproteins and all exhibited indoleacetic acid (IAA) oxidase activity. The percentage purity of two of the isozymes was very high; these isozymes differed in percentage carbohydrate and in peroxidase and IAA oxidase specific activities. Three of the isozymes displayed molecular weight values of about 43 000; for the fourth, molecular weight was considerably higher. Corresponding isozymes from the genotrophs and from two other flax genotypes displayed molecular weight differences which corresponded to electrophoretic relative mobility differences. Enzyme yield per unit fresh weight was higher for one genotroph than the other, and the balance between peroxidase activity and IAA oxidase activity between the genotrophs was different.

DIFFERENCES IN MOLECULAR WEIGHT BETWEEN CORRESPONDING ANIONIC PEROXIDASE ISOZYMES FROM TWO FLAX GENOTROPHS

1980 ◽  
Vol 22 (4) ◽  
pp. 529-534 ◽  
Author(s):  
H. Tyson ◽  
M. A. Fieldes
Keyword(s):  
Molecular Weight ◽  
Linear Regression ◽  
Linum Usitatissimum ◽  
Gel Electrophoresis ◽  
Relative Mobility ◽  
Anionic Peroxidase ◽  
Linum Usitatissimum L ◽  
Peroxidase Isozymes ◽  
Flax Genotrophs ◽  
Adult Plants

Anionic peroxidase isozymes from main stem tissues of adult plants of two flax (Linum usitatissimum L.) genotrophs were separated using acrylamide gel electrophoresis. A range of seven acrylamide concentrations was used for the gels, enabling the effect of gel concentration on relative mobility (Rm) to be examined. The regression of log (Rm) on gel concentration was linear for two of the four main isozymes found. Differences in linear regression slope between the L and S flax genotroph isozymes suggested genotroph differences in molecular weight.

The heme moiety in peanut peroxidase

1984 ◽  
Vol 62 (11) ◽  
pp. 1046-1050 ◽  
Author(s):  
R. N. Chibbar ◽  
R. Cella ◽  
R. B. Van Huystee
Keyword(s):  
Peroxidase Activity ◽  
Active Site ◽  
Oxidase Activity ◽  
Indoleacetic Acid ◽  
Iaa Oxidase ◽  
Equimolar Ratio ◽  
Immunological Properties ◽  
Peanut Peroxidase

Heme is present in an equimolar ratio to the apoprotein in the major cationic fraction of peanut peroxidase. The removal of heme from the holoenzyme does not affect the physicochemical and immunological properties of the apoperoxidase, however peroxidase activity is completely lost. The indoleacetic acid (IAA) oxidase activity of the apoperoxidase is reduced to 1/20 of the original holoenzyme. Both the peroxidase and IAA-oxidase activity could partially be restored in the holoenzyme reconstituted with hemin. It is suggested that heme may also participate in the IAA-oxidase activity possibly by altering the active site.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: V. A PRELIMINARY EXAMINATION OF THE LEVEL OF FREE ENDOGENOUS INDOLEACETIC ACID IN RUSTED AND MILDEWED CEREAL LEAVES AND THEIR ABILITY TO DECARBOXYLATE EXOGENOUSLY SUPPLIED RADIOACTIVE INDOLEACETIC ACID

1958 ◽  
Vol 36 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Michael Shaw ◽  
A. R. Hawkins
Keyword(s):  
Oxidase Activity ◽  
Indoleacetic Acid ◽  
Sharp Decrease ◽  
Inhibiting Activity ◽  
Growth Substances ◽  
Fresh Weight ◽  
Avena Coleoptile ◽  
Preliminary Examination ◽  
Growth Promoting ◽  
Host Parasite

The growth substances were extracted with cold alcohol from the first leaves of uninfected, rusted (wheat), and mildewed (barley) cereal seedlings. The acid ether fractions were chromatographed on paper and the chromatograms were cut into sections which were assayed for growth promoting or inhibiting activity in the Avena coleoptile straight growth test. The estimated, free, endogenous indoleacetic acid content of uninfected leaves ranged from 0.5 to 3.2 μg. per kilogram fresh weight. In the early stages of infection this decreased, but increased again to from 5 to about 10 μg. per kilogram fresh weight by the 10th day after the inoculation of susceptible hosts. Indoleacetic acid was not detected in ungerminated uredospores of stem rust (race 15B), but two other growth promoting substances appeared to be present.Leaf disks were incubated with radioactive indoleacetic acid (as —C14OOK) and the radioactivity released as C14O2 was measured. The ability of the tissue to decarboxylate the indoleacetate (‘oxidase’ activity) increased sharply, sometimes to as much as 1000%, in the first 3 days after inoculation. With susceptible hosts, this increase was followed by an almost equally sharp decrease to less than 50% of the values for uninfected tissue. With infected, resistant tissue, the secondary decrease in ‘oxidase’ activity was delayed and less pronounced.The results are discussed and a working hypothesis suggested with respect to the relation between susceptibility or resistance and the auxin balance.

Peroxidase activity and relative mobility at anthesis in flax genotrophs and their F2 progeny: developmental and genetic effects

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 495-504 ◽  
Author(s):  
M. A. Fieldes ◽  
J. Ross
Keyword(s):  
Genetic Control ◽  
Peroxidase Activity ◽  
Stem Elongation ◽  
Genetic Regulation ◽  
Relative Mobility ◽  
Activity Data ◽  
Peroxidase Isozymes ◽  
Developmental Age ◽  
Total Peroxidase Activity ◽  
Flax Genotrophs

The genetic regulation of the environmentally induced heritable difference in peroxidase activity between Durrant's large (L) and small (S) flax genotrophs was examined in leaves from plants ranging in developmental age from 6 days before anthesis to 3 days after. Mean peroxidase activity was higher for S than L and intermediate for the reciprocal F2's from L × S and S × L crosses (F2L × S and F2S × L). However, activity increased with development and, since there were small but significant differences in the average developmental ages of L, S, F2L × S, and F2S × L plants, the effects of development on activity had to be taken into account in examining the F2 activity data for segregation. A regression method was used to remove developmental effects and, underlying these effects, total peroxidase activity appeared to be regulated by a single locus with two alleles and L dominance. Two other dimorphic loci, both described previously, were also examined. One regulates the presence-absence of septa hairs in the seed capsules and the other the relative mobility of anionic peroxidase isozymes. There was no phenotypic linkage between the three segregating parameters. The genetic control of activity appeared to regulate cationic rather than anionic activity. In addition, a relationship between activity and plant height indicated either that peroxidase activity is one of the factors regulating main stem elongation or that the locus regulating peroxidase activity is linked to one of the loci involved in the regulation of plant height.Key words: flax genotrophs, peroxidase, genetic control, development.

Characterization of the α-amylase Receptor of Streptococcus gordonii NCTC 7868

1990 ◽  
Vol 69 (11) ◽  
pp. 1746-1752 ◽  
Author(s):  
C.W.I. Douglas
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Binding Activity ◽  
Streptococcus Gordonii ◽  
Putative Receptor ◽  
Pre Treatment ◽  
Culture Supernatants ◽  
Very High ◽  
True Relationship

The purpose of the work described here was to investigate the mechanisms involved in the binding of salivary α-amylase to Streptococcus gordonii NCTC 7868 (Challis). Of six types of a-amylase studied, only mammalian forms of the enzyme were found to bind to S. gordonii cells. Salivary a-amylase binding was inhibited by treatment of cells with trypsin and pronase, but not with pepsin or sodium periodate. Presence of starch, dextrin, or maltoheptaose partially inhibited binding of the enzyme to S. gordonii. Both mutanolysin extracts of cells and culture supernatants contained α-amylase-binding activity, which was partially purified by Sepharose CL-6B and DEAE-ionexchange chromatography. Western blotting detected four putative receptor bands-65 kDa, 15 kDa, 12.5 kDa, and one with a very high molecular weight; the lower-molecular-weight components may be products of proteolytic degradation of the high-molecular-weight material, but their true relationship has yet to be determined. Pre-treatment of salivary α-amylase with these putative receptors partially inhibited subsequent binding of the enzyme to S. gordonii cells. When bound to cells, only 19% of the salivary α-amylase activity was detectable, suggesting that α-amylase binds to the receptor at or near the active site of the enzyme.

The regulation of peroxidase activity by gibberellin and auxin in pea stem segments

1973 ◽  
Vol 51 (11) ◽  
pp. 2237-2242 ◽  
Author(s):  
Ralph Ockerse ◽  
Laura M. Mumford
Keyword(s):  
Peroxidase Activity ◽  
Oxidase Activity ◽  
Actinomycin D ◽  
Indoleacetic Acid ◽  
Growth Media ◽  
Slight Reduction ◽  
Iaa Oxidase ◽  
Pisum Sativum L ◽  
Reduced Activity ◽  
Stem Segments

Peroxidase activity in excised stem segments of Pisum sativum L. cv. Progress No. 9 increases linearly during incubation in buffered medium. Gibberellic acid (GA) causes a slight reduction in activity whereas indoleacetic acid (IAA) treatment completely prevents this rise. Excision produces two new cathodic isoperoxidases near the cut ends. Their appearance is prevented by cycloheximide, actinomycin D, and IAA; G A enhances this IAA-induced repression. GA alone stimulates one of the isozymes but does not affect the other one. Peroxidase leakage is stimulated by GA and inhibited by IAA treatment. The activity is entirely confined to the isoperoxidases produced in response to injury.IAA oxidase activity in incubated segments was slightly elevated over that of freshly cut ones. However, differences in activity among hormone treatments were small. IAA oxidase was also demonstrated in growth media and only IAA treatment reduced activity. Both peroxidases in the medium were isolated by column chromatography. Surprisingly, the purified isozymes appear to be essentially devoid of IAA oxidase activity.

Evidence for heterogeneity in the carbohydrate moieties of peroxidase isozymes from two environmentally induced flax genotrophs

1986 ◽  
Vol 64 (11) ◽  
pp. 2682-2687 ◽  
Author(s):  
Pierre-Richard Gaudreault ◽  
Hugh Tyson
Keyword(s):  
Molecular Weight ◽  
Affinity Chromatography ◽  
Concanavalin A ◽  
Posttranslational Modification ◽  
Stem Tissue ◽  
Carbohydrate Composition ◽  
Molecular Weights ◽  
Peroxidase Isozymes ◽  
Flax Genotrophs ◽  
Carbohydrate Chains

The corresponding isoperoxidases from the flax genotrophs L and S have different molecular weights. Utilizing affinity chromatography on Sepharose-bound concanavalin A, we have shown that this lectin has a stronger affinity for the isoperoxidases purified from S stem tissue than those from L. The presence of differences in the carbohydrate composition of L and S peroxidases was confirmed when it was observed that only S peroxidases were susceptible to digestion by endo-β-N-acetylglucosaminidase H. Glycoprotein-enriched fractions were then purified from L and S stem tissue. The results showed that most glycoproteins of S origin have higher molecular weights than their L counterparts. Certain glycoproteins were digested by endo-β-N-acetylglucosaminidase H only if they were of S origin, while others were digested regardless of their origin. In both cases, the original differences in molecular weight between L and S glycoproteins were eliminated. These results support our view that posttranslational modification at the level of the carbohydrate chains of the L and S peroxidases is the reason for their heterogeneity on polyacrylamide gels.

COMPARATIVE THERMAL STABILITY OF PEROXIDASE ISOZYMES FROM TWO FLAX GENOTROPHS

1982 ◽  
Vol 24 (4) ◽  
pp. 427-435 ◽  
Author(s):  
Mary Ann Fieldes ◽  
Hugh Tyson
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Prolonged Treatment ◽  
Linum Usitatissimum L ◽  
Peroxidase Isozymes ◽  
Heat Treated ◽  
Peak Areas ◽  
Flax Genotrophs ◽  
Thermal Stability Of

The thermal stability of peroxidase isozymes was examined in vitro in Linum usitatissimum L. Extracts of main stem tissues of the L and S genotrophs produced by Durrant were heat treated over a range of temperatures and times. Isozymes in treated extracts were separated electrophoretically, and peak areas for the four main anionic isozymes, together with their relative mobilities (Rms), were recorded. Peak areas supplied estimates of relative activities. Short duration treatments at 60° and 70 °C demonstrated differences in thermal stability between isozymes and produced changes in Rm. With prolonged treatment at 40 °C, the thermal stability of one isozyme differed from those of the other three. This isozyme was known to have a higher molecular weight than the others. In addition, prolonged treatment at 40 °C demonstrated increased thermal stability of the three lower molecular weight isozymes of genotroph S compared to those of L.

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