Amino acid sequence of human erythrocyte carbonic anhydrase B

Andersson, B. A.; Nyman, Per Olof; Strid, Lars

doi:10.1016/0006-291x(72)90400-7

Cited by 137 publications

(37 citation statements)

References 15 publications

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“…Enzyme concentration were estimated spectrophotometrically at280nm takingAi2 = 16.3cm-' [13]andamolecularweight of 28 850 [14]. Isotopically enriched chemicals, 'H20 (99.8 '2)) and Ba13C03 (90%) were obtained from Stohler Isotope Chemicals.…”

Section: Enzyme and Chemicalsmentioning

confidence: 99%

A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I

Simonsson

Jonsson

Lindskog

1982

European Journal of Biochemistry

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Rates of COz/HCO; exchange, catalyzed by human carbonic anhydrase I (or B) at chemical equilibrium, were estimated from the nuclear magnetic resonance linewidths of '3C-labeled substrates. The results show that the maximal exchange rate constant is independent of pH in the range 5.7-8.0, whereas the apparent substrate dissociation constant depends on pH. Exchange proceeds rapidly in the absence of added buffers, and the addition of buffers has negligible effects on exchange rates. Exchange is equally rapid with 'HzO or 2Hz0 as solvents. Chloride ions inhibit CO;!/HCO; exchange competitively.The maximal exchange rates obtained with human carbonic anhydrase I are 50 times slower than those obtained with human isoenzyme I1 (or C). From a comparison of the exchange kinetics with the steady-state kinetics of COz hydration and HCOY dehydration it is tentatively concluded that the transfer of H + between active site and medium proceeds with rates of similar magnitudes in the two isoenzynies, whereas the central catalytic step, the interconversion of enzyme-bound COz and HCO;, is much slower in isoenzyme 1 than in isoenzyme 11.Carbonic anhydrase is a zinc-containing metalloenzyme catalyzing the reversible reaction COz + HzO G HCO; + H'.(1) Three isoenzyme types are known to occur in mammals [I]. These have homologous structures indicating common ancestry, and they have different kinetic properties. Carbonic anhydrase I1 (or C) is an extremely efficient catalyst with a CO;! hydration turnover number of lo6 s-' at pH 9 and 25 "C. Carbonic anhydrase I (or B) is less efficient, and the corresponding turnover number is about 10' s-'. Isoenzyme 111 is found in skeletal muscle and has an even lower activity than isoenzyme I. The structural basis of these kinetic differences remains obscure.We have previously performed a series of kinetic studies of human and bovine carbonic anhydrase I1 [2-61. The results can be summarized in a kinetic scheme the main feature of which consists of two half reactions:The interconversion of EH and E-in Eqn (3) is complex involving at least two reaction steps, probably an intramolecular proton transfer [2,7] and a proton transfer between an active-site group and a buffer molecule, which may be regarded as a second substrate [4,8,9]. The rate of exchange between COz and HCOY (Eqn2) can be estimated independently of the proton transfers of Eqn (3) by measuring the enzyme-catalyzed line broadening of 13C NMR resonances of labeled Substrate under equilibrium conditions [lo]. Our previous studies [5] showed that maximal rates of COz/ Enzyme. Carbonic anhydrase (EC 4.2.1.1) HCO; exchange, catalyzed by human carbonic anhydrase 11, are faster that the maximal turnover rates so that turnover must be rate-limited by a step or steps involved in proton transfer between the active site and the medium.We have, then, asked the question if the lower activity of isoenzyme I depends on a slower rate of CO;!/HCOY exchange or a slower rate of proton transfer according to Eqn (3) or both. In this paper we present a ...

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Section: Enzyme and Chemicalsmentioning

confidence: 99%

A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I

Simonsson

Jonsson

Lindskog

1982

European Journal of Biochemistry

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“…Enzyme concentrations were determined spectrophotometrically at 280 nm using E = 49 mM-' . cm-' and M, = 28 850 (Andersson et al, 1972;Nyman and Lindskog, 1964). The degree of purity of the preparations was checked by SDS/polyacrylamide gel electrophoresis and was greater than or equal to 95%.…”

Section: Methodsmentioning

confidence: 99%

Catalytic and Inhibitor‐Binding Properties of Some Active‐Site Mutants of Human Carbonic Anhydrase I

Engstrand

Jonsson

Lindskog

1995

European Journal of Biochemistry

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Three isozyme-specific residues in the active site of human carbonic anhydrase I, Va162, His67, and His200, have been changed by site-directed mutagenesis to their counterparts in human carbonic anhydrase 11, Asn62, Asn67, and Thr200. A double mutant, containing Asn62 and Asn67, and a triple mutant, containing all three alterations, were also produced. The rates of CO, hydration and ester hydrolysis catalyzed by these mutants, the inhibition of these enzymes by the anions, SCN-, and I-, and the binding of the sulfonamide inhibitors, dansylamide and MK-417 (a thienothiopyran-2-sulfonamide) have been measured. The results suggest that the effect of His200 in isozyme I is to prolong the lifetime of the enzyme-bicarbonate complex and to increase the pK, of the catalytic group, a zinc-coordinated water molecule. For isozyme I, Val62 and His67 might interfere with the function of a proton 'shuttle' group in the active site, thus maintaining the buffer specificity of a compulsory proton-transfer step. The single mutations have small effects on anion binding. Only the triple mutant has anion-binding properties resembling those of isozyme 11. All mutants show altered sulfonamide-binding properties. In particular, the binding specificity is affected. While wild-type isozyme I binds dansylamide SO times more strongly than MK-417, the triple mutant shows a reversed selectivity and binds MK-417 nearly SO times more strongly than dansylamide.

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“…The A isozyme, identical to the B isoforms, and the C enzyme were later designated as CAI and CAII, respectively, and this is still their acronyms. During 1970s, the amino acid sequences and X-ray crystal structures were reported for both human CAI and CAII [12][13][14][15][16] . During the same decade, a sulfonamide-resistant CA activity was discovered in male rat liver homogenates 17,18 and in chicken muscle tissue 19 .…”

Section: Introductionmentioning

confidence: 99%

A magnificent enzyme superfamily: carbonic anhydrases, their purification and characterization

Guler

Capasso

Supuran

2015

Journal of Enzyme Inhibition and Medicinal Chemistry

130

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In this paper, we reviewed the purification and characterization methods of the a-carbonic anhydrase (CA, EC 4.2.1.1) class. Six genetic families (a-, b-, g-, d-, z-and Z-CAs) all know to date, all encoding such enzymes in organisms widely distributed over the phylogenetic tree. Starting from the manuscripts published in the 1930s on the isolation and purification of a-CAs from blood and other tissues, and ending with the recent discovery of the last genetic family in protozoa, the Z-CAs, considered for long time an a-CA, we present historically the numerous and different procedures which were employed for obtaining these catalysts in pure form. a-CAs possess important application in medicine (as many human a-CA isoforms are drug targets) as well as biotechnological processes, in which the enzymes are ultimately used for CO 2 capture in order to mitigate the global warming effects due to greenhouse gases. Recently, it was discovered an involvement of CAs in cancerogenesis as well as infection caused by pathogenic agents such as bacteria, fungi and protozoa. Inhibition studies of CAs identified in the genome of the aforementioned organisms might lead to the discovery of innovative drugs with a novel mechanism of action.

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Amino acid sequence of human erythrocyte carbonic anhydrase B

Cited by 137 publications

References 15 publications

A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I

A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I

Catalytic and Inhibitor‐Binding Properties of Some Active‐Site Mutants of Human Carbonic Anhydrase I

A magnificent enzyme superfamily: carbonic anhydrases, their purification and characterization

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Amino acid sequence of human erythrocyte carbonic anhydrase B

Cited by 137 publications

References 15 publications

A 13C Nuclear Magnetic Resonance Study of CO2/HCO−3 Exchange Catalyzed by Human Carbonic Anhydrase I

A 13C Nuclear Magnetic Resonance Study of CO2/HCO−3 Exchange Catalyzed by Human Carbonic Anhydrase I

Catalytic and Inhibitor‐Binding Properties of Some Active‐Site Mutants of Human Carbonic Anhydrase I

A magnificent enzyme superfamily: carbonic anhydrases, their purification and characterization

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A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I

A ¹³C Nuclear Magnetic Resonance Study of CO₂/HCO⁻₃ Exchange Catalyzed by Human Carbonic Anhydrase I