Golgi apparatus definition

Many enzymes are located in specific compartments such as mitochondria, cell wall, endoplasmatic reticulum, Golgi apparatus, and lysosomes restricting the possible substrates, effectors and other enzymes with which they interact. A well known example is the membrane bound enzymes which can only exert their effect on molecules located very near the respective membranes. This set-up allows different reactions which would otherwise compete to occur simultaneously in different parts of the cell. In this connection it should be remembered that access of metabolites to the different cellular compartments is usually intensively regulated and controlled. Unfortunately, in general, the definition and access-restrictions for the diverse cellular compartments are incompletely known at present. 

Histochemical studies indicate that ascorbic acid is highly concentrated in the Golgi apparatus, and mitochondrial elements in the animal cell (Bourne, 1935) and these show changes in scorbutic animals which are rectified when ascorbic acid is supplied (Miwa, 1939). The most definite evidence we have as yet of the site of formation within the cell comes, as we have already seen, from the work of Mapson et al. (1954), who have shown that at least one stage in the synthesis is catalyzed by enzymes localized within the mitochondria. These observations have now been extended to animals, where very similar results have been obtained with mitochondria from liver tissue (Isherwood et al., 1954). 

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