Enzymes localization

Kempner E S and Miller J FI 1968 The molecular biology of Euglena gracilis V. Enzyme localization Exp. Cell. Res. 51 150-6... 

A three-dimensional meshwork of proteinaceous filaments of various sizes fills the space between the organelles of all eukaryotic cell types. This material is known collectively as the cytoskeleton, but despite the static property implied by this name, the cytoskeleton is plastic and dynamic. Not only must the cytoplasm move and modify its shape when a cell changes its position or shape, but the cytoskeleton itself causes these movements. In addition to motility, the cytoskeleton plays a role in metabolism. Several glycolytic enzymes are known to be associated with actin filaments, possibly to concentrate substrate and enzymes locally. Many mRNA species appear to be bound by filaments, especially in egg cells where they may be immobilized in distinct regions thereby becoming concentrated in defined tissues upon subsequent cell divisions. 

In this chapter we report recent analytical applications of CL imaging for the detection of biospecific reactions in macrosamples such as microtiter plates of different format (96 or 384 wells), filter membranes and irregular surfaces represented by specimens related to the cultural heritage, and results obtained when the CCD detector is coupled with optical microscopy for enzyme localization, immunohistochemical reactions, and complementary DNA (cDNA) detection (Table 1). 

Gene donor Enzyme localization in the host and other notes Ref. 

ACE is a rather nonspecific peptidase that can cleave C-terminal dipeptides from various peptides (dipeptidyl carboxypeptidase). As kininase 11, it contributes to the inactivation of kinins, such as bradykinin. ACE is also present in blood plasma however, enzyme localized in the luminal side of vascular endothelium is primarily responsible for the formation of angiotensin 11. The lung is rich in ACE, but kidneys, heart, and other organs also contain the enzyme. 

Arachnids (scorpions, spiders, and ticks) Scorpions Stinger - neurotoxin, no enzymes Localized pain, mostly dangerous to children... 

Chan-Palay V, Hochh M, Jentsch L, et al Raphe serotonin neurons in the human brain stem in normal controls and patients with senile dementia of the Alzheimer type and Parkinsons disease relationship to monoamine oxidase enzyme localization. Dementia 3 253-269, 1992... 

Urata, K., and Satoh, T. (1991). Enzyme localization and orientation of the active site of dissimilatory nitrite reductase from Bacillus firmus. Arch. Microbiol. 156, 24-27. 

Fig. 1 Enzymes localized to B. hominis mitochondrial-like organelle. The enzymes are 1 malic enzyme, 2 pyruvate NADP oxidoreductase, 3 acetate succinate CoA transferase, 4 succinate thiokinase, 5 a-ketoglutarate dehydrogenase, 6 isocitrate dehydrogenase, and 7 aconitase...

There is thus some evidence for the tight binding of enzymes, especially glycosidases, to cell walls in both dicots and monocots. The nature and localization of these enzymes suggest that they may, perhaps, play a role in wall breakdown and such other processes as elongation growth. The membrane systems of plant cells are known to be involved in the transport, and introduction, of polysaccharides into the cell wall247-249 enzymes localized in the wall may also play a part in the metabolism of these polymers when they are transferred from the membrane system to the wall. 

Where within the mitochondria are specific enzymes localized One approach to this question is to see how easily the enzymes can be dissociated from mitochondria. Some enzymes come out readily under hypotonic conditions. Some are released only upon sonic oscillation, suggesting that they are inside the matrix space. Others, including the cytochromes and the flavoproteins that act upon succinate and NADH, are so firmly embedded in the inner mitochondrial membranes that they can be dissociated only through the use of non-denaturing detergents. 

Kohler JJ, Bertozzi CR. Regulating cell surface glycosylation by small molecule control of enzyme localization. Chem. Biol. 2003 10 1303-1311. 

Once the number of antennae is established, further extension is possible through addition of backbone polymers and terminal structures similar to those found on mucin-type glycans. LacNAc polymers can be added to any of the aforementioned GlcNAcs (Fig. 4A, w-x). Similarly, these polymers can be elaborated with fucose, sulfate, and sialic acid added in the same linkages described for mucin-type structures (Fig. 4A, y-z). Most fucosyltransferases and sulfotransferases, as well as the sialyltransferases that cap polyLacNAc, are capable of modifying both O-linked and A-linked glycans some exhibit a preference for one or the other. These biases are likely a result of differences in enzyme localization. 

---