Amino Acids and Protein Synthesis in Developing Wheat Endosperm

Jennings, AC; Morton, R. K.

doi:10.1071/bi9630384

Cited by 36 publications

(23 citation statements)

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“…The chemical and cytological evidence (Jennings and Morton 1963b;Jennings, Morton, and Palk 1963) would support the suggestion that, in the earliest stages of development ( Figs. 1 and 2), the proteins extracted by dilute alkali are derived from the rather large amounts of lipoprotein membrane material in the endosperm cells.…”

Section: Discussionmentioning

confidence: 61%

“…Graham, Morton, and Raison (1963) concluded that the incorporation of amino acids into their "high-speed supernatant" fraction (or proteins extracted by pyrophosphate buffer) preceded that into the small "protein bodies". These protein bodies had an amino acid composition rather similar to that of the proteins extracted by dilute alkali from the same preparation of endosperm (Jennings and Morton 1963c). Graham, Morton, and Raison (1963) and Morton, Raison, and Smeaton (1964) also found that their protein body preparations contained significant amounts of proteins which were soluble in pyrophosphate buffer.…”

Section: Discussionmentioning

confidence: 87%

“…It is perhaps pertinent that Jennings and Morton (1963b) found, in the developing endosperm, the phosphorus: nitrogen ratio in the protein fraction isolated by the procedure of Martin and remained relatively constant from about 18 days after flowering, indicating the presence of phosphorylated groups in one or more of the proteins. Phospholipids may also be synthesized at an appropriate rate (Jennings and Morton 1963b).…”

Section: Discussionmentioning

confidence: 99%

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The Characterization by Electrophoresis of the Proteins Extracted by Dilute Alkali From Wheat Flour

Jennings¹

1968

Aust. Jnl. Of Bio. Sci.

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SummaryProcedures have been developed for characterizing, in a chemically unaltered form, the proteins usually extracted in dilute alkali from wheat flour or endosperm.The electrophoretic zone patterns of the proteins migrating to the cathode in this fraction were qualitatively identical with those of a previously described high·speed supernatant fraction of wheat endosperm. In addition, there was a slow movement of proteins to the anode.Intermolecular disulphide bonds do not appear to be present in flour or formed during the preparation of a dough.It is concluded that most of the proteins previously considered to be of cytoplasmic origin are storage proteins. The following mechanism is proposed for the formation, in developing endosperm, of the protein fraction extracted by alkali. The proteins soluble in pyrophosphate buffer are neutralized by proteins, or other compounds, with a net negative charge at physiological pH values and which are synthesized in stoichiometric amounts. These complexes may then interact mainly through hydrophobic bonds to form aggregates insoluble in dilute aqueous buffers and dilute acids.It is concluded that there are two types of storage proteins, synthesized by separate systems. One type is characterized, in gel electrophoresis, by relatively low mobilities, the other by relatively high mobilities.

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Section: Discussionmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 87%

Section: Discussionmentioning

confidence: 99%

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The Characterization by Electrophoresis of the Proteins Extracted by Dilute Alkali From Wheat Flour

Jennings¹

1968

Aust. Jnl. Of Bio. Sci.

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“…The pattern of changes in the levels of protein and RNA reported in this study have previously been reported in grains of maturing rice (29,30), wheat (14), and corn (10). Studies on developing wheat grain (7) have shown that during the period of rapid increase in endospermal protein, a related increase in RNA content occurs.…”

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confidence: 56%

Biochemical Factors Affecting Protein Accumulation in the Rice Grain

1970

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Rice grains (Oryza sativa L.) from three varieties and three pairs of lines with different protein content were collected at 4-day intervals from 4 to 32 days after flowering. The samples were analyzed for protein, free amino nitrogen, ribonucleic acid, protease activity, and ribonuclease activity. In addition, the capacity of the intact grain to incorporate amino acids was determined for the three pairs of lines. The maximal level of free amino nitrogen and the capacity of the developing grain to incorporate amino acids were consistently found to be higher in the samples with the high protein content in the mature grain. The ribonucleic acid content of the grain tended to be higher in the high protein samples.The protein content of brown rice (Oryza sativa L.) ranges from about 5 to 17% (15, 16, 18). The level of protein in the mature grain has been found to be consistently higher in some varieties than in others (18). However Sample Collection. Grain samples were collected from 4 to 32 days after flowering at 4-day intervals. Spikelets were examined daily and tagged when they flowered because the flowering dates of the spikelets of a single panicle, as well as of the panicles of different tillers of a single plant ranged over several days. The grains were cooled to 0 C in an ice bath immediately after sampling and were stored at -20 C until used for analysis. However, freshly collected samples were used for assaying synthetic capacity because this activity was found to decrease progressively at -20 C.Moisture Determination. One hundred grains kept frozen over Dry Ice were dehulled by hand, then placed in tared 15-ml test tubes. The weight loss during freeze-drying for 48 hr was taken as the moisture content.Homogenization. The grains from the moisture determination were soaked overnight at 0 C in 13.5 ml of 0.05 M tris buffer (pH 7.5) with 0.5 M KCl (the volume of 100 freeze-dried grains had previously been found to be about 1.5 ml). The soaked grains were homogenized at 0 C for 3 min with a VirTis 45 homogenizer at top speed. Six milliliters of the homogenate were set aside to be used for the determination of protein content, nucleic acid, and free amino nitrogen. About 9 ml were centrifuged at 500g for 15 min at 4 C, and the supernatant fluid was reserved for assaying ribonuclease activitiy.Chemical Determinations. Six milliliters of the crude homogenate (equivalent to 40 grains) were treated with 6 ml of cold, 20% (w/v) trichloroacetic acid for 1 hr at 0 C and then fractionated according to the scheme shown in Figure 1.Free Amino Nitrogen. The amount of soluble amino nitrogen in extract I was determined by using the ninhydrin method described by Moore Protein. The residue from the trichloroacetic acid washings was suspended in enough1 N NaOH to make a total volume of 25 ml.The mixture was aged for 30 min, heated at 100 C for 10 min, mixed, and then allowed to stand overnight. The gelatinous precipitate was removed by filtering through Whatman No. 541 paper. A portion of the filtrate (0.1 ml) was d...

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“…Coates and Simmonds (1961) have also isolated protein fractions from wheat flour which have a relatively high arginine content although the studies of Graham, Morton, and Raison (1963), Jennings and Morton (1963), and Morton, Palk, and Raison (1964) have not indicated that endosperm protein bodies are rich in arginine.…”

Section: Introductionmentioning

confidence: 99%

Localization of Arginine-Rich Proteins in Mature Seeds of some Members of the Gramineae

Fulcher¹,

O’Brien²,

Simmonds³

1972

Aust. Jnl. Of Bio. Sci.

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Several mature grass seeds (Triticum aestivum L., Avena sativa L., Andropogon sorghum Brot., Echinochloa utilis Ohwi & Yabuno, and Lolium perenne L.) were fixed and embedded in glycol methacrylate. Thin (1-2 p.m) sections were examined by light microscopy after staining specifically for arginine residues or basic proteins. The aleurone protein bodies of all seeds stained intensely by these methods but there was considerable variation in concentration and organization of the argininerich basic proteins in endosperm tissue of the various seeds. Amino acid analysis was used to confirm the histochemical differences in basic amino acid concentration between the aleurone layer and endosperm of T. aBstivum.

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Amino Acids and Protein Synthesis in Developing Wheat Endosperm

Cited by 36 publications

References 5 publications

The Characterization by Electrophoresis of the Proteins Extracted by Dilute Alkali From Wheat Flour

The Characterization by Electrophoresis of the Proteins Extracted by Dilute Alkali From Wheat Flour

Biochemical Factors Affecting Protein Accumulation in the Rice Grain

Localization of Arginine-Rich Proteins in Mature Seeds of some Members of the Gramineae

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