Proteolytic activity in maize leaves

Klein, Michal; Harpaz, I.

doi:10.1016/s0031-9422(00)86179-8

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…Used to measure activity against CTN was a modification of the procedure of Klein and Harpaz (17). The reaction mixture contained 1.4 ml of 0.1 M sodium phosphate, pH 6.2, and 0.2 ml of cell-free extract, and was started by the addition of 0.2 ml of 2 mm CTN in acetone.…”

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confidence: 99%

“…The reaction mixture contained 1.4 ml of 0.1 M sodium phosphate, pH 6.2, and 0.2 ml of cell-free extract, and was started by the addition of 0.2 ml of 2 mm CTN in acetone. After 10 min at 28 C the reaction was stopped with 0.2 ml of 50% trichloroacetic acid, the precipitated protein was removed by centrifugation, and the absorbance of the supernatant solution was measured at 320 nm (17). Activity against ANA was followed in a spectrophotometer at 310 nm at 28 C by the procedure of Burger et al (2).…”

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confidence: 99%

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Loss of Ribulose 1,5-Diphosphate Carboxylase and Increase in Proteolytic Activity during Senescence of Detached Primary Barley Leaves

Peterson¹,

Huffaker²

1975

Plant Physiol.

205

118

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(5,12,13,14) and Perilla (10) leaves. Fraction I protein as usually isolated can probably be considered to be crude RuDPCase' since it often contains several other enzymatic activities in addition to that of RuDPCase (15,18,36). We recently reported that intact barley seedlings placed in extended darkness lost soluble protein, almost all of which was accounted for by the enzyme RuDPCase (9,25). The results of these investigations are not surprising, since this enzyme is considered to be the major storage protein of many plant leaves (18,26). Since RuDPCase is also principally responsible for net fixation of CO2 in plants, its fate during senescence is important. This study is a further extension to show the effects of some chemicals and light on the loss of RuDPCase and to correlate the concurrent development of proteases and esterases during senescence. Evidence is also presented for the turnover of RuDPCase under these conditions. The process of senescence has been studied in intact plants, detached leaves, and leaf discs in both light and dark (31, 37). In general, senescence is speeded by detaching the leaves and/or imposing darkness. Perhaps the most striking changes in senescence are losses of Chl, nucleic acids, and protein (39), accompanied by a general increase in proteolytic activity as measured in vitro. Cytokinins (32,33,37) or light (7)

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confidence: 99%

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confidence: 99%

Loss of Ribulose 1,5-Diphosphate Carboxylase and Increase in Proteolytic Activity during Senescence of Detached Primary Barley Leaves

Peterson¹,

Huffaker²

1975

Plant Physiol.

205

118

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“…In a number of instances the crude enzyme-extract of the plant was partially purified on a DEAE-cellulose column, in a manner described by KLEIN and HARPAZ (1965), eluting the fraction with the highest proteolytic activity at 0.2 M of NaCl. An improvement of this method was the "reinforcement" of the 0.01 M phosphate buffer solution pH 6.2used throughout the purification procedure, including the final stage of dialyzing-out the "NaCl -by 0.01 M of eadi one of the two afore-mentioned stabilizers, cystein and EDTA.…”

Section: Methodsmentioning

confidence: 99%

“…It should be pointed out in this connection that proteolysis in leaf or stalk tissue of maize is so weak that measuring it by the previously known methods entailed certain difficulties. Hence, a newer method was developed for this particular purpose, based on the cleavage by maize sap of a synthetic substrate sudi as carbobenzoxy-L-tyrosine p-nitrophenyl ester (KLEIN and HARPAZ 1965). However, it was later found that the latter could be dispensed with since, under proper conditions, maize tissue extract can exhibit a safely measurable rate of proteolysis also on a real protein substrate, sudi as casein, within no longer than 120 minutes of incubation (see following chapter).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Infection with Maize rough dwarf virus (MRDV) upon the Proteolytic Activity in Maize Plants

Klein

Harpaz

1968

J Phytopathol

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Summary An improved method for assaying the proteolytic enzyme activity in maize plant sap is described. Using this method, the level of proteolysis in MRDV‐infected plants was compared to that of non‐infected ones. Up to 24 days after inoculation, no significant differences could be noticed between healthy and infected plants. However, on the 35th day after inoculation the rate of proteolysis in infected leaf sap was some 17 percent higher than that of non‐infected plants. In sap extracted from maize stalks, the difference was even higher, reaching over 23 percent. Following partial purification of the sap by fractionation of a DEAE‐cellulose column, these differences could be augmented to above 80 percent. Zusammenfassung Mit einer verbesserten Methode wurde die proteolytische Enzymaktivität in gesunden und an Rauhverzwergung erkrankten Maispflanzen verglichen. Bis 24 Tage nach der Infektion traten keine bedeutsamen Unterschiede auf. Nach 35 Tagen war die proteolytische Aktivität im Saft infizierter Blätter etwa 17% und im Saft der Stengel mehr als 23% höher als in den Kontrollen. Nach teilweiser Reinigung der Säfte durch Fraktionierung an DEAE‐Cellulose stiegen diese Unterschiede auf über 80%.

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“…Protease. The enzyme was assayed by a modification of the method of Klein and Harpaz (1965) based on the finding that many proteolytic enzymes are able to hydrolyse the weak peptide bond in «-carbobenzoxy L-tyrosine /)-nitrophenyl ester (CTN) and also the ester linkage. Below pH 7 activity was measured by the absorption maximum at 340 m/( of the ^-nitrophenol released.…”

Section: Enzvme Assavsmentioning

confidence: 99%

CHANGES IN THE ENZYME ACTIVITY OF SOLUBLE PROTEIN FRACTIONS IN THE COURSE OF FOLIAR SENESCENCE IN PERILLA FRUTESCENS (L.) BRITT.

Kannangara

Woolhouse

1968

New Phytologist

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SUMMARYSeparation of the soluble proteins from leaves of Perilla by means of gel filtration on a Sephadex Gioo column yielded two protein bands with molecular weights of approximately 400,000 and 23,000, which appear to correspond to the well-known Fraction I and Fraction II proteins respectively. The amount of Fraction I protein in the leaves decreased progressively from the time that the leaves became fully expanded whilst the amount of Fraction II protein decreased only in the later stages of senescence. Aleasurements of the activity of several enzymes in successive 4 ml fractions from the column showed that each occupied a different peak position within the two main protein fractions. Fach of the enzymes assayed showed a different pattern of change in the course of senescence of the leaves. These changes in protein content and enzyme activity are discussed in relation to earlier observations on the physiological functioning of senescing leaves of Perilla.

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Proteolytic activity in maize leaves

Cited by 6 publications

References 7 publications

Loss of Ribulose 1,5-Diphosphate Carboxylase and Increase in Proteolytic Activity during Senescence of Detached Primary Barley Leaves

Loss of Ribulose 1,5-Diphosphate Carboxylase and Increase in Proteolytic Activity during Senescence of Detached Primary Barley Leaves

The Effect of Infection with Maize rough dwarf virus (MRDV) upon the Proteolytic Activity in Maize Plants

CHANGES IN THE ENZYME ACTIVITY OF SOLUBLE PROTEIN FRACTIONS IN THE COURSE OF FOLIAR SENESCENCE IN PERILLA FRUTESCENS (L.) BRITT.

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