Spectroscopic studies on the interaction of phosphate with uteroferrin.

Doi, Kei; Gupta, Rajeev; Aisen, Philip

doi:10.1016/s0021-9258(18)48190-2

Cited by 17 publications

(8 citation statements)

References 24 publications

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“…Apparently the presence of the additional noncatalytic subunit protects the enzyme against oxidation during purification. Considerable controversy has surrounded the identification of a reduced phosphate complex, 139,141,142,144,145 and spectroscopic evidence to support its existence has only recently been obtained (vide infra).…”

Section: Ribonucleotide Reductasementioning

confidence: 99%

Proteins containing oxo-bridged dinuclear iron centers: a bioinorganic perspective

Vincent¹,

Olivier-Lilley²,

Averill³

1990

Chem. Rev.

393

156

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Section: Ribonucleotide Reductasementioning

confidence: 99%

Proteins containing oxo-bridged dinuclear iron centers: a bioinorganic perspective

Vincent¹,

Olivier-Lilley²,

Averill³

1990

Chem. Rev.

393

156

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“…Several oxoanions are inhibitors of uteroferrin. ,,, Phosphate (PO 4 3- ) ,− and arsenate (AsO 4 3- ) 22,45,56 are competitive inhibitors which lower the reduction potential and lead to aerobic oxidation of the site to the inactive met level ,, Molybdate (MoO 4 2- ) 49,74 and tungstate (WO 4 2- ) 74 are noncompetitive inhibitors, which are thought to interact with the active site in a different manner due to their much larger binding constants. , These anions increase the reduction potential and stabilize the half-met site .…”

Section: Introductionmentioning

confidence: 99%

“…Several oxoanions are inhibitors of uteroferrin. 42,45,51,52 Phosphate (PO 4 3-) 22, [53][54][55][56] and arsenate (AsO 4 3-) 22,45,56 are competitive inhibitors which lower the reduction potential 57 and lead to aerobic oxidation of the site to the inactive met level. 51 Magnetic susceptibility studies show that 1/2metUf has a much weaker antiferromagnetic coupling between the metal sites after the phosphate binding 36,38 and a dramatically altered EPR signal that is broad and difficult to observe.…”

Section: Introductionmentioning

confidence: 99%

Circular Dichroism and Magnetic Circular Dichroism Studies of the Mixed-Valence Binuclear Non-Heme Iron Active Site in Uteroferrin and Its Anion Complexes

1997

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Uteroferrin (Uf) is a purple acid phosphatase for which the reduced [Fe II Fe III ] form of the enzyme is catalytically active in the hydrolysis of phosphate esters. The binuclear non-heme iron active site of the native reduced enzyme (1/2metUf) and its molybdate-and phosphate-bound forms have been studied with absorption (ABS), circular dichorism (CD), and magnetic circular dichroism (MCD) spectroscopies to probe their geometric and electronic structure. CD and MCD in the UV-Vis region give the tyrosine (phenolate) to Fe III charge transfer bands which probe the ferric center. CD and MCD in the NIR region probe the d-d transitions of both the Fe II and the Fe III centers. Variable-temperature variable-field (VTVH) MCD combined with EPR data are analyzed to determine the g values and energies of the ground state and the excited sublevels. These parameters are further interpreted in terms of a spin Hamiltonian model, which includes the zero-field splitting (ZFS) of Fe II and Fe III centers and the exchange coupling (J) between the irons due to bridging ligation. These ground and excited-state results confirm that both irons are six-coordinate with a µ-OH bridge. Anions bind to the active site in a bridging mode, which perturbs the ground and excited states of both iron centers. In particular, the exchange coupling decreases, µ-OH bridge f Fe II bonding strength increases, and the Tyr f Fe III donor interaction increases upon the phosphate binding. These results are correlated with the recent X-ray crystal structure of the kidney bean purple acid phosphatase, which contains an Fe III Zn II active site. These studies provide geometric and electronic structure insight into the hydrolysis reaction mechanism of this enzyme.

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“…Phosphate is known to inhibit the reduced enzyme reversibly without the presence of oxygen, and this phosphate can be removed reversibly from PAP. Since vanadate is a phosphate analog, similar modes of interaction may take place between the purple acid phosphatase and vanadate Doi et al, 1987;Pyrz et al, 1986;Day et al, 1988; David & Que, 1990; Wang et al, 1991), and the nature of the interaction is explored in further detail below.…”

Section: Inhibition Of Purple Acid Phosphatase By Vanadatementioning

confidence: 99%

“…Anion interactions with the purple acid phosphatases (PAPs) are particularly important for understanding the detailed mechanism of phosphate ester hydrolysis (Vincent & Averill 1991;Doi et al, 1987). PAPs are distinguished from other phosphatases because PAP contains a diiron center that can exist in two oxidation states: a catalytically active Fe(II)-Fe(III) form and an inactive Fe(III)-Fe(III) form.…”

mentioning

confidence: 99%

Interaction of porcine uterine fluid purple acid phosphatase with vanadate and vanadyl cation

Crans¹,

Simone²,

Holz³

et al. 1992

Biochemistry

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Uteroferrin, the purple acid phosphatase from porcine uterine fluid, is noncompetitively inhibited by vanadate in a time-dependent manner under both aerobic and anaerobic conditions. This time-dependent inhibition is observed only with the diiron enzyme and is absent when the FeZn enzyme is used. The observations are attributed to the sequential formation of two uteroferrin-vanadium complexes. The first complex forms rapidly and reversibly, while the second complex forms slowly and results in the production of catalytically inactive oxidized uteroferrin and V(IV), which is observed by EPR. The redox reaction can be reversed by treatment of the oxidized enzyme first with (V(IV)) and then EDTA to generate a catalytically active uteroferrin. Multiple inhibition kinetics suggests that vanadate is mutually exclusive with molybdate, tungstate, and vanadyl cation. The binding site for each of these anions is distinct from the site to which the competitive inhibitors phosphate and arsenate bind. The time-dependent inhibition by vanadate of uteroferrin containing the diiron core represents a new type of mechanism by which vanadium can interact with proteins and gives additional insight into the binding of anions to uteroferrin.

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Spectroscopic studies on the interaction of phosphate with uteroferrin.

Cited by 17 publications

References 24 publications

Proteins containing oxo-bridged dinuclear iron centers: a bioinorganic perspective

Proteins containing oxo-bridged dinuclear iron centers: a bioinorganic perspective

Circular Dichroism and Magnetic Circular Dichroism Studies of the Mixed-Valence Binuclear Non-Heme Iron Active Site in Uteroferrin and Its Anion Complexes

Interaction of porcine uterine fluid purple acid phosphatase with vanadate and vanadyl cation

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