The amino acid content of the proteins of barley grains

Folkes, B. F.; Yemm, E. W.

doi:10.1042/bj0620004

Cited by 53 publications

(28 citation statements)

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“…Methods for the estimation of these proteins in small quantities of barley flour were developed by Bishop (1928Bishop ( , 1929a. Similar methods were adopted in the present investigation, certain modifications being introduced to ensure that the fractions separated coincided as closely as possible with the large-scale preparations of barley proteins analysed by Folkes and Yemm (1956). Justification for these modifications is given in the second part of this section, in which the identity of the various protein fractions is discussed.…”

Section: Methods For Analysis Of Endospermsmentioning

confidence: 99%

“…In an earlier paper of this series (Folkes, Willis and Yemm, 1952), a general account was given of this movement of nitrogen into the embryo, and more recently fairly complete analyses of the amino-acid content of the proteins of the endosperm and embryo have been described (Yemm and Folkes, 1953;Folkes and Yemm, 1956). It was evident from the wide differences in composition between the chief storage proteins of the endosperm and the protoplasmic proteins of the embryo that an extensive interconversion of amino-acids must occur during germination.…”

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The Respiration of Barley Plants

Folkes¹,

Yemm²

1958

New Phytologist

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With 6 figures in the text)When barley grains are germinated in absence of external supplies of nitrogen, their metabolism of amino-acids and proteins is dominated by the transformation of reserves, stored in the endosperm, into protoplasmic proteins and other nitrogenous constituents of the young embryo. In an earlier paper of this series (Folkes, Willis and Yemm, 1952), a general account was given of this movement of nitrogen into the embryo, and more recently fairly complete analyses of the amino-acid content of the proteins of the endosperm and embryo have been described (Yemm and Folkes, 1953;Folkes and Yemm, 1956). It was evident from the wide differences in composition between the chief storage proteins of the endosperm and the protoplasmic proteins of the embryo that an extensive interconversion of amino-acids must occur during germination.In the present paper data are given which permit a more exact estimate of the nature and extent of these interconversions. Methods have been developed whereby barley seedlings could be analysed at various stages of germination and estimates made of the amounts of the protein fractions whose amino-acid composition has already been described. The results of these estimations, taken together with analyses of the nonprotein constituents, yield a fairly complete account of the quantitative changes in the various amino-acids during germination. The interconversions thus revealed have been considered in terms of the mechanisms involved and in relation to the respiratory process of the seedlings. MATERIAL AND CULTUREThe conditions used in the culture of Spratt Archer barley for this investigation have already been fully described by Folkes et al. (1952). The seedlings were grown in pots of sand, supplied with a mineral nutrient solution lacking nitrogen. The pots were placed beneath a battery of electric lamps in a thermostatically controlled room at 22.5' C. and were illuminated at approximately 500 ft. candles for 16 hours each day. Three separate experiments contribute to the results given here and a different batch of barley was used for each experiment. Experiment I was with a low nitrogen barley in which the ungerminated grain had a nitrogen content of 1.6 per cent of the dry weight, Experiment II employed a medium nitrogen barley of 2.0 per cent nitrogen and Experiment HI a high nitrogen barley with a nitrogen content of 2.5 per cent.Beff)re planting, the grain was sterilized and depaleated, and an initial sample for 106

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Section: Methods For Analysis Of Endospermsmentioning

confidence: 99%

mentioning

confidence: 99%

The Respiration of Barley Plants

Folkes¹,

Yemm²

1958

New Phytologist

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“…There is lit-tIe doubt that these bodies are the sites of accumulation of the storage protein. Folkes and Yemm (1956) showed that, on germination, the endosperm of barley provided directly over 70% of the amino acid residues of the developing embryo. Moreover, the additional amino acid requirement of the embryo was provided by synthesis from the excess glutamine and proline of the endosperm protein.…”

Section: (B) Ohanges In Amino Acids Of Endosperm Dnring Developmentmentioning

confidence: 99%

Amino Acids and Protein Synthesis in Developing Wheat Endosperm

Jennings¹,

Morton²

1963

Aust. Jnl. Of Bio. Sci.

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The amino acid composition of several protein fractions of developing wheat endosperm (cv. Gabo, grown in 1960 in Adelaide) was determined by ion-exchange chromatography. There were considerable differences in the compositions of the fractions extracted by pyrophosphate, acetic acid, and by sodium hydroxide. The composition of the fraction extracted by acetic acid remained relatively constant during development whereas there were changes in the compositions of the fractions extracted by pyrophosphate buffer, and by sodium hydroxide.The amino acid composition of the total protein body fraction, at day 18 and at day 46 after flowering, showed little change during development. However, there was considerable difference in composition between the total protein body fraction and a fraction of small protein bodies obtained by gradient centrifugation.The results suggest that the amino acid composition of the protein bodies may change during growth and development of the protein body. The number of protein bodies increase during development of the endosperm; the increase in the amount of residues of amino acids in the protein body fraction during endosperm development confirms that the protein bodies are the sites of accumulation of storage proteins in endosperm.

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“…These amino acids provide nitrogen to synthesize new proteins and nucleic acids. Folkes and Yemm (8) have concluded that the major losses of glutamate, asparagine and prolinie in germinatinig barley could be accounted for in chlorophyll, other amino acids and other bases. However, although many amino acids were deficient in maize roots, these deficiences were not removed by other amino acids (14) and extensive conversions of the carbon from glutamate or leucine into those amino acids which were limiting did not occur (16).…”

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confidence: 99%