Enzymes schematic representation

FIGURE 7.43. Addition of streptavidin to the biotinylated polystyrene amphiphile (left) results in a biohybrid monolayer, which can be further funtionalized by the addition of biotinylated proteins/enzymes (schematic representation in the middle). TEM image of a ferritin-streptavidin-polystyrene monolayer. Each black spot represents a single ferritin. 

Fig. 2. Immobilized enzymes. Schematic representation of an artificial cell, containing urease and albumin-coated active charcoal as an absorbent for uric acid, ammonia and creatinine. A 10 ml suspension of these 20 pm-diameter urease capsules corresponds to a surface area of 20,000 cm, which Is larger than that of the conventional artificial kidney.

Figure 37 The SMAT family of enzymes schematic representation of primary structural similarities, (A) The aminotransferase subfamily contains a conserved lysine (K) residue. (B) The dehy-drase subfamily (DH-E,) contains a histidine (H) residue in the same position and several conserved cysteine (C) residues, mostly concentrated in an insert. The N-tcrminal region of similarity (stippled) arid two commonly conserved motifs in both sequences are indicated.

Functionalized conducting monomers can be deposited on electrode surfaces aiming for covalent attachment or entrapment of sensor components. Electrically conductive polymers (qv), eg, polypyrrole, polyaniline [25233-30-17, and polythiophene/23 2JJ-J4-j5y, can be formed at the anode by electrochemical polymerization. For integration of bioselective compounds or redox polymers into conductive polymers, functionalization of conductive polymer films, whether before or after polymerization, is essential. In Figure 7, a schematic representation of an amperomethc biosensor where the enzyme is covalendy bound to a functionalized conductive polymer, eg, P-amino (polypyrrole) or poly[A/-(4-aminophenyl)-2,2 -dithienyl]pyrrole, is shown. Entrapment of ferrocene-modified GOD within polypyrrole is shown in Figure 7. 

Fig. 7. Schematic representation of enzyme covalently bound to a functionalized conductive polymer where ( ) represents the functional group on the polymer and (B) the active site on the enzyme (42). Courtesy of the American Chemical Society.

FIGURE 18.5 Schematic representation of types of multienzyme systems carrying out a metabolic pathway (a) Physically separate, soluble enzymes with diffusing intermediates, (b) A multienzyme complex. Substrate enters the complex, becomes covalently bound and then sequentially modified by enzymes Ei to E5 before product is released. No intermediates are free to diffuse away, (c) A membrane-bound multienzyme system. 

Fig. 9.1 Schematic representation of possible mechanisms of resistance in Gram-negative and Gram-positive bacteria. 1, antibiotic-inactivating enzymes 2, antibiotic efflux proteins 3, alteration or duplication of intracellular targets 4, alteration of the cell membrane reducing antibiotic uptake 5, alterations in porins or lipopolysaccharide reducing antibiotic uptake or binding.

Figure 1.3. Schematic representation of an enzyme-catalyzed reaction. Enzymes often match the shape of the substrates they bind to, or the transition state of the reaction they catalyze. Enzymes are highly efficient catalysts and represent a great source of inspiration for designing technical catalysts.

Figure 3.1 Schematic representation of a generic excitatory synapse in the brain. The presynaptic terminal releases the transmitter glutamate by fusion of transmitter vesicles with the nerve terminal membrane. Glutamate diffuses rapidly across the synaptic cleft to bind to and activate AMPA and NMDA receptors. In addition, glutamate may bind to metabotropic G-protein-coupled glutamate receptors located perisynaptically to cause initiation of intracellular signalling via the G-protein, Gq, to activate the enzyme phospholipase and hence produce inositol triphosphate (IP3) which can release Ca from intracellular calcium stores...

Fig. 2. Schematic representation of various PTS enzymes and their domains (taken from [3]). The different domains are indicated as follows transmembrane hydrophobic domain IIC) the E-II domain...

Figure 17.17 Schematic representation of a single-compartment glucose/02 enzyme fuel cell built from carbon fiber electrodes modified with Os -containing polymers that incorporate glucose oxidase at the anode and bilirubin oxidase at the cathode. The inset shows power density versus cell potential curves for this fuel cell operating in a quiescent solution in air at pH 7.2, 0.14 M NaCl, 20 mM phosphate, and 15 mM glucose. Parts of this figure are reprinted with permission from Mano et al. [2003]. Copyright (2003) American Chemical Society.

A schematic representation of the metabolism of lipoproteins is shown in Fig. 12 [170]. Chylomicrons are synthesized and secreted by the small intestine. They are hydrolyzed in blood by the enzyme lipoprotein lipase... 

Figure 1.6 Schematic representation of the changes in protein conformational microstate distribution that attend ligand (i.e., substrate, transition state, product and inhibitor) binding during enzyme catalysis. For each step of the reaction cycle, the distribution of conformational microstates is represented as a potential energy (PE) diagram.

Fig. 11.2. Schematic representation of the primary structure of secreted AChE B of N. brasiliensis in comparison with that of Torpedo californica, for which the three-dimensional structure has been resolved. The residues in the catalytic triad (Ser-His-Glu) are depicted with an asterisk, and the position of cysteine residues and the predicted intramolecular disulphide bonding pattern common to cholinesterases is indicated. An insertion of 17 amino acids relative to the Torpedo sequence, which would predict a novel loop at the molecular surface, is marked with a black box. The 14 aromatic residues lining the active-site gorge of the Torpedo enzyme are illustrated. Identical residues in the nematode enzyme are indicated in plain text, conservative substitutions are boxed, and non-conservative substitutions are circled. The amino acid sequence of AChE C is 90% identical to AChE B, and differs only in the features illustrated in that Thr-70 is substituted by Ser.

Fig. 1.3 Schematic representation of the entrapped enzyme in a silica matrix (left side). Enzymatic activity, under extreme alkaline conditions, of acid phosphatase (A) immobilized in silica sol-gel matrices with or without CTAB, or (B) in solution. Reprinted with permission from [56]. Copyright 2005, American Chemical Society.

Fig. 7.2 Schematic representation of the procedure for the encapsulation of enzyme in PE microcapsules (I) and preparing nanoporous protein particles (II) using MS spheres as templates.

FIGURE 5.6 Schematic representation of the immunosensor based on a Protein A-GEB biocomposite as a transducer, (a) Immobilization of RlgG on the surface via interaction with Protein A, (b) competitive immunoassay using anti-RIgG and biotinylated anti-RIgG, (c) enzyme labeling using HRP-streptavidin and (d) electrochemical enzyme activity determination. (Reprinted from [31] with permission from Elsevier.)... 

Fig. 6.10. Schematic representation of a selective delivery obtained by targeting a cell-specific peptidase, a) The drug itself permeates passively into all cells, and no selectivity is achieved. b) The target cells contain a specific enzyme, which activates the prodrug in situ, c) The target cells produce a specific enzyme, which activates the prodrug in their vicinity. Note that cases b and c are not mutually exclusive and may, in fact, occur simultaneously.

Fig. 6.13. Schematic representation of a selective delivery obtained by antibody-directed en-zyme-prodrug therapy (ADEPT). An exogenous enzyme is coupled to a monoclonal antibody (mAb) targeted for tumor cells. In a second step, a prodrug is administered, which, as a selective substrate of the exogenous enzyme, will be selectively activated at the tumor site.

Fig. 6.14. Schematic representation of selective delivery obtained by gene-directed enzyme-prodrug therapy (GDEPT). The gene encoding an exogenous enzyme is transferred to tumor cells, where it is to be expressed. In a second step, a prodrug is administered that is selectively activated at the tumor site by the exogenous enzyme expressed by the tumor cells.

Fig. 9.1. Schematic representation of the ubiquitin-proteasome pathway. Ubiquitin moiecuies are activated by an El enzyme (shown green at 1 /3 scaie) in an ATP-dependent reaction, transferred to a cysteine residue (yeiiow) on an E2 or Ub carrier protein and subsequentiy attached to amino groups...

Figure 3. Schematic representation of the interplay of the various epigenetic marks and its therapeutic potential DNA methylation causes the concomitant deacetylation of the histones, whereby it negatively (—) coixelates with histone acetylation and positively (+) with histone methylation, particularly the repressive marks. The active methylation marks correlate positively with histone acetylation. The loss of activity or the loss or mistargeting of these activities are the most common cause of epigenetic diseases. Shown in the boxes are the small molecular modulators (a, activators or i, inhibitors) of the various enzymes that have potential to develop epigenetic therapeutics...

Figure 1 Schematic representation of tomato ACS poiypeptide with marked a-heiicai and /3-strand secondary structure regions (according to PDB with entry code 1 iAX), residues criticai for cataiysis, and fragments of the poiypeptide representing the iarge and the smaii domain in the spatiai structure of enzyme. Open biocks denote a-heiicai regions and fiiied biocks, /3-strand regions. For detaiis see Sections 5.04.2.2.4 and 5.04.2.2.5.

Fig. 7 Schematic representation of the conformational differences (highlighted with a dotted box) exhibited by aminoglycosides in the binding pockets of RNA (a) and some of the enzymes involved in bacterial resistance (b). The glucose, 2-deoxy-streptamine and ribose units are numbered as I, II and III respectively...

Fig. 2. Schematic representation of paclitaxel biosynthesis. Dimethylallyl-diphosphate and isopentenyl-diphosphate are condensed through geranylgeranyl diphosphate synthase activity to render geranylgeranyl-diphosphate (GGPP). GGPP is converted into taxa-4(5), 11 (12)-diene in a reaction catalyzed by the taxane synthase (TS). A series of reactions catalyzed by cytochrome P450 monoxygenases lead to the production of a taxane intermediate that is further converted to baccatin III through enzymes-driven oxidation and oxetane ring formation. The side chain moiety of paclitaxel is derived from L-phenylalanine. Three consecutive arrows mean multiple steps. Ac, acetyl Bz, benzoyl.

Fig. 1. Schematic representation of protein kinase C. The cartoon shows the different domains of PKC in the inactive form of the enzyme...

FIGURE 1.6 Schematic representation of cell-based sensor (CBB) for pathogen detection. After binding to receptor on mammalian cells, pathogen or toxin will aid in the release of signaling molecules such as fluorescence or enzyme that can be detected using an appropriate sensor. 

Figure 8-2. Pathway for synthesis of palmitate by the fatty acid synthase (FAS) complex. Schematic representation of a single cycle adding two carbons to the growing acyl chain. Formation of the initial acetyl thioester with a cysteine residue of the enzyme preceded the first step shown. Acyl carrier protein (ACP) is a component of the FAS complex that carries the malonate covalently attached to a sulfhydryl group on its phosphopantatheine coenzyme (-SH in the scheme).

---