Modern methods of plant analysis
01 Jan 1964-
About: The article was published on 1964-01-01 and is currently open access. It has received 1991 citations till now.
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TL;DR: Three genes (gpd1, gpd2, and gpd3) encoding glyceraldehyde-3-phosphate dehydrogenase were isolated from the dimorphic zygomycete Mucor circinelloides by PCR using degenerated primers, indicating that gpd1 is the major transcribed gpd gene.
71 citations
71 citations
TL;DR: U- PME and B-PME created differently modified pectins that vary in degree and length of multiple attacks and fraction of the pectin population that was modified.
71 citations
TL;DR: The present study indicates that lipid peroxidation induced membrane permeability could partly be the result of higher lipoxygenase activity during full bloom.
71 citations
TL;DR: Nutritional properties of the preparations are discussed in relation to their amino acid composition and to their known in vivo and in vitro behaviour, and sufficient lysine, both total and nutritionally ‘available’, is present in unfractionated and cytoplasmic protein, though it may be marginal in some chloroplastic fractions.
Abstract: Extracts from leaves of barley (Hordeum vulgare), lupin (Lupinus albus) and Chinese cabbage (Brassica chinensis) of different ages were fractionated. As the leaves age, chloroplasts are increasingly disrupted during extraction and the chlorophyll-containing protein becomes increasingly difficult to sediment. The amount of protein unassociated with chlorophyll varies with species, but not with leaf age.
Analyses are given of selected chloroplastic fractions (sedimented and coagulated) and of the protein precipitated from the whole extracts and the various supernatant fluids. Amino acid composition of unfractionated protein is independent of species, except perhaps for methionine; leaf age has no affect on composition. The method of protein precipitation may influence the amount of lysine determined. Contrary to previous reports, chloroplastic and cytoplasmic protein do not have the same composition.
Nutritional properties of the preparations are discussed in relation to their amino acid composition and to their known in vivo and in vitro behaviour. Comparison with the F.A.O. reference protein shows that sufficient lysine, both total and nutritionally ‘available’, is present in unfractionated and cytoplasmic protein, though it may be marginal in some chloroplastic fractions. The first limiting essential amino acid in all leaf protein preparations is methionine, and there is an adequate amount ‘available’ in cytoplasmic but not in unfractionated or chloroplastic protein. Reasons are suggested for the unavailability of methionine, and possibly cyst(e)ine, in the latter preparations.
70 citations
References
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01 Jan 1963
TL;DR: In this article, a physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln.
Abstract: Kann ein physiologischer Vorgang auf eine enzymatische Wirkung zuruckgefuhrt werden (vgl. S. 301), so besteht die folgende Aufgabe darin, Naheres uber die Eigenschaften des beteiligten Enzyms zu ermitteln. Hierzu gehoren die Bestimmung der Reaktions- und Substratspezifitat sowie die Ermittlung der Bedingungen, unter denen eine optimale Wirkung des Enzyms gegeben ist. Wesentlich zur Charakterisierung ist ferner die Untersuchung der Stabilitat des Enzyms und dabei insbesondere die Feststellung, ob es sich um ein Ferment handelt, das zur vollen Aktivitat dialysable Cofaktoren benotigt. Falls diese Frage bejaht wird, ist auch die Bestimmung der unerlaslichen Cofaktoren anzuschliesen. Uberdies bietet auch der Nachweis der Lokalisation des Enzyms in der Zelle (oder im Zellverband) eine entscheidende Moglichkeit zur Charakterisierung des Fermentes. Hinzu kommt schlieslich noch die Untersuchung der Wirkung einzelner Inhibitoren1 auf das Enzym, die zu weitgehender Klarung des Reaktionsmechanismus beitragen kann und eine Abgrenzung der Eigenschaften des untersuchten Fermentes gegenuber ahnlichen Enzymen erlaubt.
2 citations
01 Jan 1962
TL;DR: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins and rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
Abstract: Optical rotation has been found to be one of the most convenient methods of following the denaturation of proteins. Generally speaking denaturation can be defined as a process or sequence of processes in which the spatial arrangement of the polypeptide chains within the molecule is changed from that typical of the native protein to a more disordered arrangement (Kauzmann 1959). The terms “configuration”, “conformation” and “state of folding” are widely used for spatial arrangement. It is probably best to follow the suggestion of Blout (1960) and restrict the use of “configuration” to its original sense, i.e. the spatial arrangement around an asymmetric carbon atom, and to use “conformation” for the shape of the molecule in its entirety. The properties discussed in the previous Chapter i.e., viscosity, diffusion, sedimentation, and light scattering — can all furnish information on the overall shape of proteins or other macromolecules and changes in this shape with environment. Thus Doty, Bradbury and Holtzer (1956) were able to show using these methods, together with streaming birefringence, that poly-γ-benzyl-L-glutamate could exist in two conformations, the α-helix and the solvated randomly coiled form, depending on the solvent. The change from α-helix to random coil was accompanied by marked changes in the optical rotatory properties of the polypeptides. It is to be expected that an α-helical structure should contribute to the rotatory power of a polypeptide since helices are asymmetric and not superimposable on their mirror images. The work on polypeptides has shown that rotatory dispersion is capable of providing information on the folding of the polypeptide chain in proteins and the changes accompanying denaturation.
1 citations