| | 1 | Author
| Coralie Wink, Thom As, H. Artm Ann | Requires cookie* | | | Title
| Properties and Subcellular Localization of L-Alanine: Aldehyde Aminotransferase: Concept of an Ubiquitous Plant Enzyme Involved in Secondary Metabolism  | | | | Abstract
| L-Alanine: aldehyde aminotransferase occurs ubiquitously in higher plants. The enzyme catalyzes the reaction: L-alanine + monoaldehyde -> monoamine + pyruvate; it is responsible for the formation of aliphatic plant amines and involved in the biosynthesis o f hemlock alkaloids as shown by Roberts. A continuous coupled photometric test was developed to determine the low activities of the transaminase. The enzyme from the "amine-free" plant Spinacia oleracea was purified 77-fold and separated from other aminotransferases. A comparison of the Spinacia enzyme with that isolated from spadix-appendices o f the amine-producing Arum maculatum during anthesis revealed very similar characteristics in pH-dependence, ATm-values for alanine and aliphatic aldehydes, and inhibition by 2-oxoacids. In contrast to the Spinacia enzyme the Arum aminotransferase is rapidly inactivated in the absence o f pyridoxal-5'-phosphate. The enzymes o f S. oleracea, A. maculatum and Mercurialis perennis are localized in mitochondria, but not in chloroplasts or peroxisomes. The results are discussed in relation to the function o f alanine: aldehyde aminotransferase in secondary metabolism. It is suggested that some enzymes may be expressed in plants at low levels, even in the absence o f any metabolic function. | | | |
Reference
| Z. Naturforsch. 36c, 625 (1981); received April 13 1981 | | | |
Published
| 1981 | | | |
Keywords
| Spinacia oleracea, Arum maculatum, Alanine: Aldehyde Aminotransferase, Amine-Biosynthesis, Subcellular Localization, Mitochondria | | | |
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| default:Reihe_C/36/ZNC-1981-36c-0625.pdf | | | | Identifier
| ZNC-1981-36c-0625 | | | | Volume
| 36 | |
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