Rabbit muscle

There are two distinct groups of aldolases. Type I aldolases, found in higher plants and animals, require no metal cofactor and catalyze aldol addition via Schiff base formation between the lysiae S-amino group of the enzyme and a carbonyl group of the substrate. Class II aldolases are found primarily ia microorganisms and utilize a divalent ziac to activate the electrophilic component of the reaction. The most studied aldolases are fmctose-1,6-diphosphate (FDP) enzymes from rabbit muscle, rabbit muscle adolase (RAMA), and a Zn " -containing aldolase from E. coli. In vivo these enzymes catalyze the reversible reaction of D-glyceraldehyde-3-phosphate [591-57-1] (G-3-P) and dihydroxyacetone phosphate [57-04-5] (DHAP). 

FIGURE 19.24 A mechanism for the phosphoglycerate mutase reaction in rabbit muscle and in yeast. Zelda Rose of the Institute for Cancer Research in Philadelphia showed that the enzyme requires a small amount of 2,3-BPG to phosphorylate the histidine residue before the mechanism can proceed. Prior to her work, the role of the phosphohistidine in this mechanism was not understood. 

Jervis used porous silica coated with chemisorbed polyacrylhydrazide for immobilization of adenosine monophosphate (AMP) [117]. After periodate oxidation of its ribose residue the ligand was coupled to the carrier and used for isolation of lactate dehydrogenase from rabbit muscle. The specific capacity was 2 mg of protein/g adsorbent with a ligand content of 10 pmol/g, whereas recovery of enzymatic activity after elution was 85%. Hipwell et al. [118] found that for effective binding of lactate dehydrogenases on AMP-o-aminoalkyl-Sepharose the spacer arm length required at least 4 methylene links. Apparently, a macromolecule of polyacrylhydrazide acts itself like an extended spacer arm and thus allow AMP to bind the enzyme. 

The only commercially available enzyme, FruA from rabbit muscle (class 1), is the most widely investigated, however, it is also the most sensitive under commonly used reaction conditions4. The other types, which can be isolated from overexpressing bacterial sources5-8, typically... 

R)-2-Hydroxy-3-thiopropanal (Table 5), which could not be isolated from the reaction mixture, can be directly converted into 6-thio-D-wnimo-2-hexulose (7%) and 6-thio-L-xylo-2-hexulose (93 %) via rabbit muscle aldolase catalyzed condensation with dihydroxyacetonephos-phate28. 

Bock, P.E. Frieden, C. (1976). Phosphofructokinase I. Mechanism ofpH-dependent inactivation and reactivation of the rabbit muscle enzyme. II. Role of ligands in pH-dependent structural changes of the rabbit muscle enzyme. J. Biol. Chem. 251, 5630-5643. 

The class I FruA isolated from rabbit muscle aldolase (RAMA) is the aldolase employed for preparative synthesis in the widest sense, owing to its commercial availability and useful specific activity of 20 U mg . Its operative stability in solution is limiting, but the more robust homologous enzyme from Staphylococcus carnosus has been cloned for overexpression [87], which offers unusual stability for synthetic purposes. Recently, it was shown that less polar substrates may be converted as highly concentrated water-in-oil emulsions [88]. 

Literally hundreds of aldehydes have so far been tested successfully by enzymatic assay and preparative experiments as a replacement for (18) in rabbit muscle FruA catalyzed aldol additions [16,25], and most of the corresponding aldol products have been isolated and characterized. The rabbit FruA can discriminate racemic dl-(18), its natural substrate, with high preference for the D-antipode, but kinetic enantioselec-tivity for nonionic aldehydes is rather low [84,89]. 

In our laboratory, we have focused our attention on the syntheses of various analogs of creatine, 17, a substrate for the enzyme creatine kinase from rabbit muscle (2). The reaction catalyzed by this enzyme is... 

Attention has been drawn to the potential of phosphoric acid anhydrides of nucleoside 5 -carboxylic acids (14) as specific reagents for investigating the binding sites of enzymes. For example, (14 B = adenosine) inactivates adenylosuccinate lyase from E. coli almost completely, but has little effect on rabbit muscle AMP deaminase. The rate of hydrolysis of (14) is considerably faster than that of acetyl phosphate, suggesting intramolecular assistance by the 3 -hydroxyl group or the 3-nitrogen atom. 

The concept of a biocatalytic membrane electrode has been extended to the use of a tissue slice as the catalytic layer. An example of this approach is an electrode for AMP which consists of a slice of rabbit muscle adjacent to an ammonia gas electrode. NHj is produced by enzymatic action of rabbit muscle constituents on AMP The electrode exhibits a linear range of 1.4 x 10 to 1.0 x 10 M with a response time varying from 2.5 to 8.5 min, depending on the concentration. Electrode lifetime is about 28 days when stored between use in buffer with sodium azide to prevent bacterial growth. Excellent selectivity enables AMP to be determined in serum. 

Wang S, Wang X, Shi W et al (2008) Detection of local polarity and conformational changes at the active site of rabbit muscle creatine kinase with a new arginine-specific fluorescent probe. Biochim Biophys Acta 1784 415 -22... 

Bloxham, D.P., and Cooper, C.K. (1982) Formation of a polymethylene bis(disulfide) inter-subunit crosslink between cys-281 residues in rabbit muscle glyceraldehyde-3-phosphate dehydrogenase using octamethylene bzs-(methane[35]thiosulfonate). Biochemistry 21, 1807. 

Davies, C.E., and Kaplan, J.G. (1972) Use of diimidoester cross-linking reagent to examine the subunit structure of rabbit muscle pyruvate kinase. Can. J. Biochem. 50, 416-422. 

Ozawa, H. (1967) Bridging reagent for protein. II. The reaction of N,N -polymethylenebis(iodoacetamide) with cysteine and rabbit muscle aldolase./. Biochem. (Tokyo) 62, 531. 

Pihl, A., and Lange, R. (1962) The interaction of oxidized glutathione, cystamine mono-sulfoxide, and tetrathionate with the -SH groups of rabbit muscle D-glyceraldehyde 3-phosphate./. Biol. Chem. 237, 1356-1362. 

Shimomura, S., and Fukui, T. (1978) Characterization of the pyridoxal phosphate site in glycogen phos-phorylase b from rabbit muscle. Biochemistry 17, 5359. 

In contrast to other analytical methods, ion-selective electrodes respond to an ion activity, not concentration, which makes them especially attractive for clinical applications as health disorders are usually correlated to ion activity. While most ISEs are used in vitro, the possibility to perform measurements in vivo and continuously with implanted sensors could arm a physician with a valuable diagnostic tool. In-vivo detection is still a challenge, as sensors must meet two strict requirements first, minimally perturb the in-vivo environment, which could be problematic due to injuries and inflammation often created by an implanted sensor and also due to leaching of sensing materials second, the sensor must not be susceptible to this environment, and effects of protein adsorption, cell adhesion, and extraction of lipophilic species on a sensor response must be diminished [13], Nevertheless, direct electrolyte measurements in situ in rabbit muscles and in a porcine beating heart were successfully performed with microfabricated sensor arrays [18],... 

Amylo-1 —> 6-glucosidase obtained by Cori and Larner218 from rabbit muscles, and R-enzyme isolated by Hobson, Whelan and Peat219 from potatoes and broad beans, are typical debranching enzymes, which will hydrolyze the 6 — 1-a-D-glucosidic linkage rather than the normal 4 —> 1-a-D linkage. These enzymes will therefore be particularly important in determinations of the fine structure of amylopectin, if they can be sufficiently well purified. 

Values of molecular weight (uncorrected for dissymmetry) have been obtained by Harrap and Manners238 from light-scattering investigations, as follows rabbit liver, 6.8 X 106 rabbit muscle, 2.8 X 109 cat liver, 10.0 X 109 fetal sheep liver, 14.8 X 106 Tetrahymena pyriformis, 9.8 X 106 and Ascaris lumbricoides, 8.8 X 106. 

Rabbit muscle homogenate binding Muscle tissue binding dominates all tissue binding and muscle binding in rabbit and human is similar Fraction unbound in muscle homogenate by dialysis [25]... 

The aldol reaction is of fundamental importance in organic chemistry and has been used as a key reaction in the synthesis of many complex natural products. There are biocatalysts for this reaction (aldolases) and one (rabbit muscle... 

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