Methionine fruit ripening

Ethylene plays an essential role in the development of plants, for example in germination, growth and fruit ripening. Carbons 3 and 4 of methionine appear to be the most important source of the gas in vivo, but the effect is also induced by externally applied gas. Acetylene and carbon monoxide are competitive with ethylene. This suggests that a metal ion is present at the ethylene receptor site, a view confirmed by the inhibition of alkene binding by dithiocarbamate. The possibility that this metal is copper is supported by the preparation of copper(I)-monoalkene complexes that show the tight binding of monoalkenes characteristic of the ethylene receptor sites of plants. ... 

L-Methionine derivatives Ethylene (D 12.1) Plants (Several tissues) Causing defoliation and fruit ripening... 

Ethylene plays an important role in a number of plant developmental processes, including senescence and abscission of leaves and flowers, responses to wounding, and the ripening of climacteric fruits (Abeles, 1973). In each case ethylene is produced from methionine (Fig. 1). The two enzymes specific to the pathway, ACC synthase and ethylene forming enzyme, increase in activity in response to wounding and during ripening,... 

C4H,N02,Mr 101.1 l,mp. 229-231 °C. A non-proteinogenic amino acid first known as a synthetic product and later isolated from pears and apples. ACC is formed from methionine via 5-adenosylmethionine with the help of ACC synthase (EC 4.4.1.14) and cleaved by ACC oxidase to the multifunctional plant growth substance ethylene which plays key roles in various plant physiological processes such as ripening of fruit, aging, germination, and response to stress. 

Ethylene is not only the most important industrial source of organic chemicals, but it also has some biochemical properties that are crucial to agriculture. Ethylene is a plant hormone that can cause seeds to sprout, flowers to bloom, fruit to ripen and fall, and leaves and petals to shrivel and turn brown. It is produced naturally by plants from the amino acid methionine via an unusual cyclic amino acid, 1 -aminocydopropane-l-carboxylic... 

It s amazing, but the simplest of all alkenes, ethylene, is an important plant hormone. Among other functions, ethylene acts to promote ripening of fruit. Moreover, production of ethylene is autocatalytic that is, a little ethylene induces the formation of more from the amino acid methionine, and its effects are magnified. Accordingly, fruits such as tomatoes and bananas are now typically shipped green in well-ventilated containers so they will arrive unspoiled. Ripening can then be started by exposure to ethylene. 

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