P-Carbonic anhydrases

Structure of p-Carbonic Anhydrase from the Red Alga, Porphyridiumpurpureum A. Proposed C02 Hydration Mechanism... 

The results of site-directed mutagenesis analysis of zinc ligands of higher plant p-carbonic anhydrase and of P. purpureum carbonic anhydrase have confirmed that zinc is essential for catalysis. X-ray fine structure data indicated that a water molecule is hydrogen bonded to the zinc-ligated Asp-151 and Asp-405. The water molecule is not directly coordinated to the zinc atom. A possible catalytic mechanism of C02 hydration cycle (211) has been proposed as given in Scheme 10. 

Istin, M., and Girard, J. P. Carbonic anhydrase and mobilisation of lamellibranchs. Calc. 

Sulfonamides derived from sulfanilamide (p-arninoben2enesulfonainide) are commonly referred to as sulfa dmgs. Although several dmg classes are characterized by the presence of a sulfonamide function, eg, hypoglycemics, carbonic anhydrase inhibitors, saluretics, and tubular transport inhibitors, the antibacterial sulfonamides have become classified as the sulfa dmgs. Therapeutically active derivatives are usually substituted on the N nitrogen the position is generally unsubstituted. These features are illustrated by the stmctures of sulfanilamide (1) and sulfadiazine (2)... 

Bertini I, Luchinat C, Scozzafava A (1982) Carbonic Anhydrase An Insight into the Zinc Binding Site and into the Active Cavity Through Metal Substitution. 48 45-91 Bertrand P (1991) Application of Electron Transfer Theories to Biological Systems. 75 1-48 Bill E, see Trautwein AX (1991) 78 1-96 Bino A, see Ardon M (1987) 65 1-28 Blanchard M, see Linares C (1977) 33 179-207 Blasse G, see Powell RC (1980) 42 43-96... 

Derivatives in the s- and p-Block Elements Supported by Poly(pyrazolyl)borato Ligation Models for Carbonic Anhydrase, Receptors for Anions, and the Study of Controlled Crystallographic Disorder Gerard Parkin... 

Determination of molecular mass of pectic enzymes The molecular mass were determined by gel filtration in a Sepharose CL-6B column (1,8 x 88cm) equilibrated and eluted with Tris-HCl 50 mM, pH 7,5 buffer, plus 100 mM KCl. Fractions (3,3 ml) were collected at a flow rate of 10 ml/h. Molecular mass markers were tyroglobulin (660 kDa) apoferritin (440 kDa) P-amylase (200 kDa) alcohol dehydrogenase (150 kDa) bovine serum albumin (66 kDa) and carbonic anhydrase (29 kDa). Urea-SDS-PAGE (7%) was carried out according to Swank and Munkres [12]. Molecular mass markers were myosin (205 kDa) p-galactosidase (116 kDa) phosphorylase b (97 kDa) bovine serum albumin (66 kDa), ovalbumin (45 kDa) and carbonic anhydrase (29 kDa). 

Figure 3. (A) Determination of molecular mass of pectic enzymes by gel filtration in Sepharose 6B. Molecular mass markers - tyroglobulin, 2- apoferritin, 3- p-amylase, 4-alcohol dehydrogenase, 5- bovine serum albumin, 6- carbonic anhydrase. (B) SDS-PAGE of pectolytic activities. Molecular mass markers 1- myosin, 2- p-galactosidase, 3- phosphorylase b, 4- bovine serum albumin, 5- ovalbumin, 6- carbonic anhydrase.

ALKYL, HYDRIDE, AND HYDROXIDE DERIVATIVES OF THE s- AND p-BLOCK ELEMENTS SUPPORTED BY POLY(PYRAZOLYL)BORATO LIGATION MODELS FOR CARBONIC ANHYDRASE, RECEPTORS FOR ANIONS, AND THE STUDY OF CONTROLLED CRYSTALLOGRAPHIC DISORDER... 

It should be noted that activity of cadmium-substituted carbonic anhydrase may be enhanced at higher pH values (ca. pH 9). See Ref. (182b) and Bauer, R. Limkilde, P. Johansen, J. T. Biochemistry 1976,15, 334. 

Figure 18 Very-high-speed gradient anion exchange chromatography of proteins. Column 0.46 x 3.5 cm ZipSep AX, 3 p. Eluent Tris-HCl, pH 8.0, operated on a gradient from 0-0.5 M NaCl. Flow rate 2ml/min. Detection UV absorbance at 280 nm. (1) Ribonuclease A, (2) carbonic anhydrase, (3) conalbumin, (4) bovine serum albumin. (Reproduced from Hatch, R. G., J. Chromatogr. Sci., 31, 469,1993. By permission of Preston Publications, A Division of Preston Industries, Inc.)...

B34. Brady, H. J. M., Sowden, J. C Edwards, M., Lowe, N., and Butterworth, P. H. W Multiple GF-1 binding sites flank the erythroid specific transcription unit of the human carbonic anhydrase I gene. FEBS Lett. 257,451-456 (1989). 

Sundaram, V., Rumbolo, P., Grubb, J., Strisciuglio, P, and Sly, W. S., Carbonic anhydrase II deficiency Diagnosis and carrier detection using differential enzyme inhibition and inactivation. Am. J. Hum. Genet. 38,125-136 (1986). 

Different enzymes exhibit different specific activities and turnover numbers. The specific activity is a measure of enzyme purity and is defined as the number of enzyme units per milligram of protein. During the purification of an enzyme, the specific activity increases, and it reaches its maximum when the enzyme is in the pure state. The turnover number of an enzyme is the maximal number of moles of substrate hydrolyzed per mole of enzyme per unit time [63], For example, carbonic anhydrase, found in red blood cells, is a very active enzyme with a turnover number of 36 X 106/min per enzyme molecule. It catalyzes a very important reaction of reversible hydration of dissolved carbon dioxide in blood to form carbonic acid [57, p. 220],... 

Fig. 3 SDS-PAGE Photograph Separation (Lane Mr and A) and activity staining (Lane B and C) of the crude filtrate of Funalia trogii. Lane Mr standard molecular weight markers ([3-galactosi-dase, 118.0 kDa bovine serum albumin, 79.0 kDa ovalbumin, 47.0 kDa carbonic anhydrase, 33.0 kDa P-lactoglobulin, 25.0 kDa and lysozyme, 19.5 kDa). Relative mobilities of the standard markers vs. common logarithms of their molecular masses were plotted.With the linear regression output, the molecular masses of the proteins in the crude filtrate were estimated (taken from [18])...

Menziani, M.C., De Benedetti, P.G., Gago, F. and Richards, W.G. (1989) The binding of benzenesulfonamides to carbonic anhydrase enzyme. A molecular mechanics study and quantitative structure-activity... 

Menziani, M.C. and De Benedetti, P. (1991) Direct and indirect theoretical QSAR modelling in sulfonamide carbonic anhydrase inhibitors, in QSAR Rational Approaches on the Design of Bioactive Compounds (eds C. Silipoand A. Vittoria), Elsevier, Amsterdam, pp. 331. 

The fact that zinc is known to be a component of an enzyme carbonic anhydrase leaves no doubt as to its physiological significance. The amount of zinc in erythrocytes seems to parallel the carbonic anhydrase activity.21 The leucocytes which appear to lack carbonic anhydrase contain about 25 times as much zinc (per cell) as do the erythrocytes.20 It seems likely that an investigation of the zinc content of different types of white blood cells coupled with a study of individuals from the standpoint of the different types of white cells present (p. 35) would lead to the discovery of substantial inter-individual differences. The wide spread in the zinc concentrations in three human spleens has already been mentioned (p. 72). A recent study has been made of the intake and excretion of zinc by 13... 

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