Free Amino-acids in the Endosperm of the Developing Coconut (Cocos nucifera)
| Autor: | N. G. Baptist |
|---|---|
| Rok vydání: | 1963 |
| Předmět: | |
| Zdroj: | Journal of Experimental Botany. 14:29-41 |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | The free amino-acids in the sap flowing from the incised inflorescence of the coconut palm (Cocos nucifera) and in the liquid and solid endosperm of the coconut at various stages of development (4-12 months from the time of opening of the spathe) have been studied by paper and ion-exchange chromatography. The chief amino-acids in the sap were in decreasing order of magnitude: glutamic acid, aspartic acid, glutamine, serine, and asparagine. Smaller amounts of threonine, alanine, y-aminobutyric acid, proline, valine, arginine, and trypto phan were found, along with traces of tyrosine, /9-alanine, lysine, histidine, leucine, isoleucine, and methionine. The chief amino-acids in the liquid endosperm of the nut until 6 months of age were alanine, glutamic acid, serine, valine, and proline with smaller amounts of asparagine, aspartic acid, glycine, threonine, leucine, isoleucine, and glutamine. The alanine, glutamic acid, proline, and y-aminobutyric acid contents of the liquid endosperm increased greatly as the solid endosperm was laid down, ultimately forming about 75 per cent, of the total free amino-acids. Nineteen amino-acids were detected at the 8-io-month stage. y-Aminobutyric acid appears in the liquid endosperm soon after the solid endosperm commences to form, and increases strikingly thereafter. It was also found in the free amino-acids of the solid endosperm at all stages of development. This amino-acid was not found in the acid hydrolysate of coconut globulin. The free amino-acids in the solid endosperm were found to reflect qualitatively the free amino-acid composition of the corresponding liquid endosperm. In addition, /3-alanine, a-aminobutyric acid, phenylalanine, and tryptophan were present in small amounts. Alanine, serine, glutamic acid, and y-aminobutyric acid increased with age of the nut while the others increased up to 6 months and then decreased, only traces being found at maturity except in the case of aspartic acid, proline, and threonine. Twenty-one amino-acids were detected in the free amino-acids of the solid endosperm. The source of the free amino-acids in the liquid endosperm and the possible use of these amino-acids for protein synthesis in the coconut are briefly discussed. |
| Databáze: | OpenAIRE |
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