Cascade included

A proteolytic cascade occurs when one peptidase activates the next in a proteolytic pathway, and this in turn activates the next and so on. This is a mechanism to amplify the initial signal, because one peptidase molecule can activate many zymogen molecules. Examples of proteolytic cascades include blood coagulation, activation of digestive peptidases in the intestine, and apoptosis. 

Additional protein constituents of the intrinsic cascade include prekallikrein, an 88 kDa protein zymogen of the protease kallikrein, and high molecular mass kininogen, a 150 kDa plasma glycoprotein that serves as an accessory factor. 

Shreedhar, V. et al., A cytokine cascade including prostaglandin E2, interleukin-4, and interleukin-10 is responsible for UV-induced systemic immune suppression, J. Immunol. 160(8), 3783-3789, 1998. 

Figure 17.10 B-lymphocyte cascade including the response of the memoiy cell. The memory cell is produced in the first response to the antigen. The response of the memory cell, shown here, is to a subsequent exposure to the antigen. It provides a faster and greater response to the same antigen. This is represented by the greater number of arrows and greater number of antibodies that are produced. Plasma cells are sometimes termed, effector cells.

Fig. 10.1. Principle of signal transduction through intracellular protein kinase cascades. The intracellular protein kinase cascades are organized in modules composed in most cases of three proteinkinases and a scaffold protein. The modules process signals that are registered, integrated and passed on at the inner side of the cell membrane by central switching stations such as the Ras protein or the Rac protein. In the case of the MAP kinase pathway, the cascade includes at least three different protein kinases. Specific regulatory processes may take effect at every level of the cascade in addition, signals may be passed from the different protein kinases to other signaling pathways.

Factor Xa and its co-factor Va form the prothrombinase complex, which activates prothrombin to thrombin. Thrombin then activates other components of the coagulation cascade, including factor V and factor VIE (which activates factor XI, in turn activating factor K), and activates factor Vni and releases it from being bound to vWF. 

Photogenerated cofactors can be employed to drive biocatalytic enzyme cascades including the photosynthetic carbon dioxide fixation process [184] (Figure 35). Photogenerated NADPH provides a two-electron relay for the insertion of CO2 into a-ketoglutaric acid (23) and pyruvic acid (21) in the presence of isocitrate dehydrogenase (IcitDH) and malic enzyme (MalE), respectively. In these photosystems, Ru(bpy)3 " acts as a photosensitizer, as a primary electron acceptor... 

Photoinduced electron-transfer in the opposite direction was demonstrated upon irradiation of the Ru(bpy)3 +-Mb system in the presence of Co +(NH3)5Cl as a sacrificial electron acceptor (Figure 44B) [244]. The photochemical reaction results in the formation of ferryl species (i.e., Fe(IV)-heme), with the intermediate formation of the porphyrin cation radical (as demonstrated using laser flash photolysis [237]). The electron-transfer cascade includes the primary oxidative quenching of the excited chromophore, Ru(bpy)3"+, by Co +(NH3)5Cl to yield Ru(bpy)3 + [E° = +1.01 V vs. SCE). The resulting oxidant efficiently takes an electron from the porphyrin ring (fcet = 8.5 x 10 s ) and the porphyrin cation radical produced further oxidizes the central iron atom, converting it from the Fe(III) state to the Fe(IV) state (/cet = 4.0 x 10 s at pH 7.5). 

The mechanism of the flu-like side effects was shown to be, for most part, related to the progressive clearance of the droplets from the blood stream. The effects are considered the natural consequence of macrophage activation during phagocytosis, which is accompanied by the release of products from the ara-chidonic acid cascade, including diverse prostaglandins and pyrogenically active cytokines. ... 

It is commonly agreed that the signal transduction cascade, which is much less understood, is also of tremendous importance in mediating the effect of psychotropics. Components of this cascade include G proteins, ion channels, second messengers, and protein kinases (Manji et al. 1995). Interindividual and crossethnic variations in the genes coding these proteins likely exist and may also be responsible for the individual variability in drug response observed clinically. 

A number of proteins of the blood clotting (coagulation) cascade (including prothrombin, and a number of other clotting factors) undergo post-translational modification in a reaction catalysed by a vitamin K-dependent carboxylase, which transforms specific Glu residues into y-carboxyglutamic acid, Gla (Fig. 4.1). In the reaction (Fig. 4.2), the dihydroquinone (reduced) form of vitamin K, KH2, is oxidised to the epoxide form, KO, by O2. The... 

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