Breath and a metabolism. Supply by energy and building blocks. Synthesis of sucrose and polisaharidov

you are: Breath and a metabolism. Supply by energy and building blocks

In Calvin's cycle - Bensona is formed, as already it was marked above, fruktozo-6-phosphate (F-6-P). This geksozofosfat can turn under the influence of specific enzymes to others fosforilirovannye geksozy, namely in gljukozo-6-fos-veils (G-6-P) and gljukozo-1-phosphate (G-1-P). Easily occurs in return transformation.

Of these three geksozofosfatov are under construction then chains of the carbohydrate molecules used for transport, storage and in synthesis reactions. That such transformations could occur, geksozofosfaty should be preliminary activated. It is usually reached as a result of their joining to nukleotidam - to the difficult ring structures similar with adenilovoj by acid ATR. The product of such reaction of joining appears nukleotidnye derivatives monosaharidov, or nukleotidsahara. More often than others meet uridindifosfogljukoza (UDPG), formed in reaction between uridintrifosfatom (UTP) and gljukozo-1-phosphate (G-l-Р). Itself UTP it is formed by an indirect way, as a result of carrying over of phosphatic group from ATR to UDP (uridindifosfatu).

Nukleotidy ATR and UTP are present at all cages because they are used along with others nukleotidami in synthesis of DNA and RNK.

Sahara are transported on a plant in the form of sucrose - disaharida, consisting of the glucose and fructose rests (fig. 5.2). Sucrose is formed in reaction between UDPG and F-6-P:

Balance of this reaction is strongly shifted towards sucrose synthesis, than possibility of accumulation given disaharida in considerable concentration is provided. For the subsequent use sucrose should undergo to splitting preliminary: enzyme invertaza kataliziruet its hydrolysis with formation of free glucose and fructose.

Energy glikozidnoj communications in such reaction is spent for nothing, being distributed between two molecules. Therefore if it is necessary to glucose and fructose disintegration in the course of breath or participation (as raw materials) in synthesis polisaharidov they should undergo again preliminary fosforilirova-niju at the expense of ATR. Processes of synthesis and sucrose disintegration demonstrate that often anabolic and katabolicheskie reactions (synthesis and disintegration reaction) go on different ways.

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