ACC 1-aminocyclopropane-l-carboxylic

Abbreviations ACC, 1-aminocyclopropane-l-carboxylic acid B, breaker stage... 

Ethylene is produced not only by higher plants but also by microorganisms. Microorganisms produce ethylene by two different pathways 2-oxoglutarate-dependent pathway926 and 2-oxo-4-methylthiobutyrate-dependent pathway 927 On the other hand, higher plants produce ethylene by ACC (1-aminocyclopropane-l-carboxylic... 

Transverse geotropism in stems is a characteristic response to ethylene. It has been reported that treatments with epibrassinolide at concentrations of 1-10 ppm accelerated ethylene production in etiolated mung bean hypocotyl segments by increasing ACC (1-aminocyclopropane-l-carboxylic acid) (7). Thus it is possible that the transverse geotropism and even the twining growth response evoked by brassinolide at 10 1-10° ppm were related to the production of ethylene. 

Acceleration of airspace formation is attributed to production of ethylene and increased cellu-lase activity in the tissue (Kawase, 1981). The sequential processes in aerenchyma development are presented by McLeod et al. (1987). They suggest that flooding first results in soil oxygen depletion, followed by depletion of root oxygen. This results in ACC (1-aminocyclopropane-l-carboxylic acid) production that requires ATP. Ethylene is produced from ACC, and this process requires oxygen and is sensitive to temperature. Ethylene produced accelerates cellulase activity that softens tissue, resulting in the formation of aerenchyma tissue. 

TAAl was also isolated from a genetic screen for weak ethylene-insensitive mutants, wei mutants, in Arabidopsis. The taalAveiS mutants have elongated roots in the presences of ACC (1-aminocyclopropane-l-carboxylate), an ethylene biosynthesis precursor, whereas in wild-type root elongation is inhibited under the same conditions. Moreover, simultaneous inactivation of TAAl and of two of its close aminotransferase related homologs, TARl and TAR2, led to developmental defects similar to those in two well-known auxin mutants [171],... 

Wounding is assumed to exert its effect at the step where SAM (=S-adenosylmethionine) is converted into ACC (1-aminocyclopropane-l-carboxylic acid), the direct precursor of ethylene. Normally this step, regulated by the enzyme ACC synthase, is rate-limiting in the cascade of events leading to ethylene production (Yang and Hoffman 1984). By means of stress the rate can be increased... 

The possibility that many organic compounds could potentially be precursors of ethylene was raised, but direct evidence that in apple fruit tissue ethylene derives only from carbons of methionine was provided by Lieberman and was confirmed for other plant species. The pathway of ethylene biosynthesis has been well characterized during the last three decades. The major breakthrough came from the work of Yang and Hoffman, who established 5-adenosyl-L-methionine (SAM) as the precursor of ethylene in higher plants. The key enzyme in ethylene biosynthesis 1-aminocyclopropane-l-carboxylate synthase (S-adenosyl-L-methionine methylthioadenosine lyase, EC 4.4.1.14 ACS) catalyzes the conversion of SAM to 1-aminocyclopropane-l-carboxylic acid (ACC) and then ACC is converted to ethylene by 1-aminocyclopropane-l-carboxylate oxidase (ACO) (Scheme 1). 

Write out a plausible step-by-step mechanism by which 1-aminocyclopropane-l-carboxylate synthase (ACC synthase) of plant tissues can form ACC from S-adenosylmethionine. This reaction requires a specific cofactor... 

Kondo S, Inoue K. 1997. Abscisic acid (ABA) and 1-aminocyclopropane-l -carboxylic acid (ACC) content during growth of Satohnishiki cherry fruit, and the effect of ABA and ethephon application on fruit quality. J Hortic Sci 72 221-227. 

Methionine is the major precursor in the biochemical pathway to ethylene (9). Ethylene is formed from carbons 3 and 4 of methionine which is degraded in reactions possibly involving free radicals and oxygen (9). Recently Adams and Yang (10,11) identified S-adenosylmethionine (SAM) and 1-aminocyclopropane-l-carboxylic acid (ACC) as intermediates in the pathway from methionine to ethylene. The sequence of reactions in the pathway... 

John, P. (1997) Ethylene biosynthesis the role of 1-aminocyclopropane-l-carboxylate (ACC) oxidase and its possible evolutionary origin. Physiol. Plantarum, 100, 583-92. 

Ethylene formation. Propose a mechanism for the conversion of -adenosylmethionine into 1-aminocyclopropane-l-carboxylate (ACC) by ACC synthase, a PLP enzyme. What is the other product ... 

Ethylene is a single, gaseous compound. It is produced when methionine is first converted to S-adenosylmethionine, and then to 1-aminocyclopropane-l-carboxylic acid (ACC) by... 

Ethylene production in plants is driven by two enzyme activities, 1-aminocyclopropane-l-carboxylate synthase (ACC synthase EC 4.4.1.14) that produces 1-aminocyclopropane acid from S-adenosylmethionine followed by aminocyclopropanecarboxylate oxidase (ACC oxidase EC 1.14.17.4) decomposing S -adenosylmethionine to ethylene, cyanide and... 

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