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Research has been conducted on the pig purple acid phosphatase (uteroferrin). The involvement of Fe (super)II, Mn (super)II and Zn (super)II in naturally occutting forms of these phosphatases has been investigated and the details are reported.

Research has been conducted on galactose oxidase. The use of pulse radiolysis in generating the oxidase's redox states is described.

Research has been conducted on the aqua ions. The preparation of these ions has been carried out and their X-ray crystal structure has been determined and is described.

Research has been conducted on the mercury-containing purple corner-shared [Mo (sub)6 HgS (sub)8 (H (sub)2 O) (sub)18] (super)8+ double cube derivative of green [Mo (sub)3 S (sub)4 (H (sub)2 O) (sub)9] (super)4+. The preparation of this derivative under the air-free conditions via the reaction with Hg (super)0 and with Hg (super)I (sub)2 is described.

Research has been conducted on the Group 14 germanium. The incorporation of this Group into the incomplete cuboidal clusters [M (sub)3 E (sub)4 (H (sub)2 O) (sub)9] (super)4+ (M=Mo, W; E=S, Se) has been investigated and the results are reported.

Research demonstrates the influence of pH on the active site and histidine87 of plastocyanin. Data suggest that the higher self-exchange rate constant of parsley plastocyanin is due to a reduction in the protonation of the upper acidic patch and its hindrance to electron transfer between the oxidation states.

Results demonstrate the substrate binding and active site substitution reactions of Fusarium galactose oxidase catalytic cycle. Data reveal that protonation and deprotonation of tyrosine-495 are blocked by the coordinated anions.

Research has been conducted on the mu (sub)3 -sulfido Re-Re bonded octahedral hexarhenium(III) clusters with chloride-pyridine terminal ligands. The results of the X-ray crystallographic studies are presented.

Pulse radiolysis and stopped-flow methods were used to measure the rate constants and free-energy plot for the reduction of the oxidized form of horse-heart cytochrome c by eight organic radicals (OR). Results suggested that all eight ORs have a similar self-exchange rate constant. The Marcus free-energy plot obtained implies that the mechanism of the electron transfer occurs in the outer sphere and that the ORs react at the same site on the cytochrome c surface for which an alternative self-exchange applies.

The properties and preparation of the group 13 elements gallium, indium and thallium and cuboidal complexes from the incomplete cuboidal [MO3S4(H2O)9]4+ were examined. The single cube [MO3InS4(H2O)12]5+ was quantitatively converted into a double cube. The double cubes were oxygen sensitive and were oxidized by hydrogen in hydrochloride solutions. The single cubes were less reactive in air and were only oxidized by hydrogen at higher levels.

Research was conducted to investigate electron transfer in ruthenium-modified plastocyanin. The oxidation of Cu+ by photogenerated Ru3+ in RuH+Pc is three orders of magnitude slower than the Cu+ -> Ru3+ reaction in the RuPc derivatives, due to the large structural rearrangement that accompanies electron transfer. Results provide evidence that Ru-modified plastocyanin is a robust model system for in-depth experimental investigations of protein-gated electron flow.

An experiment was conducted to synthesize and characterize an arsenic-containing corner-shared double-cube heteroatom derivatives of the general formula [Mo6MS8(H2O)18]8+. Different bond angles and lengths were observed with the resulting S-As-S and O-Mo-O clusters. The results reflect previous observations that shorter separations are observed in Mo-M bonds when M is the transition metal and longer when it is the main element.

An experiment was performed to synthesize and characterize the structure and reactivity of heterometallic Sn-containing single- and double-cube derivatives of [Mo3Se4(H2O)9]4+ and [W3Se4(H2O)9]4+. The short Mo-Mo bond distances shown in the results reflect metal-metal bonding, while the long Mo-Sn separations indicate non-bonding for the single cube. Almost similar quantitative yields of the redox-controlled interconversions of single and double cubes were also observed.

The charge on the inorganic complex and the extent of protonation of galactose oxide (GOase) from the Canadian wood-rot fungus Fusarium NRRL 2903 have substantial effect on the rate constants. Investigations of Tyr495Phe show that protonation occurs at Tyr-495. The reduction potential of the GOase(sub ox)/GOase(sub semi) couple E(super o)' = 400 mV vs NHE at pH 7.5 varies with pH. The effect of acetate and azide on the oxidation of GOase(sub semi) with (FeCN6)3- was investigated.

An FeIIFeII product was synthesized via two well-defined redox steps characterized by the [Cr(15aneN4)(H2O)2]2+ or CrIIL-mediated reduction of spinach and parsley ferredoxin FdI in the FeIIIFeIII state. The two-stage kinetic behavior observed in the reaction of spinach and parsley FeIIIFeIII with CrIIL required the constant binding of the chromium complex with the protein. Furthermore, the Tyr-25/Tyr-82 region of spinach ferredoxin FdI was proposed as the site for CrIIL reduction.

The corner-shared double cube (Mo6BiS8(H2O)18)(super 8+) is prepared from either a fast reaction between (Mo3S4(H2O)9)(super 4+) and BiIII with BH4- or a 3-4 day reaction with Bi metal shot. The inductively coupled plasma atomic emission spectra reveal the ratio of the Mo:Bi:S to be 6:1:8. The 8+ charge is confirmed from the determination of the 3:1 stoichiometries with the use of (Co(dipic)2)- and (Fe(H2O)6)(super 3+) as oxidants. A novel representative of the P-block main group heterometallic double cube of the type (Mo6MS8(H2O)18)(super 8+) is thus obtained.

The edge-linked double cube ((Mo3PdS4(H2O)9)2)(super 8+) is converted to the single cube (Mo3(PdX)S4(H2O)9)(super 4+) as promoted by X = 1,3,5-triaza-7-phosphaadamantane, tris(3-sulfonatophenyl)phosphine, CO, Cl-, Br- and NCS-. The first phase of the reaction is fast and is characterized by changes in color such as from purple to dark blue in the reaction with Cl-. The double cube is attained back by the elimination of X. The formation constants are high and favor the complexing of X than H2O. Mo substitution is slower with Cl-, Br- and NCS-.

The simple reaction of Sn2+ with (Mo3S4(H2O)9)4+ yields the single cube cluster Mo3SnS46+. The X-ray crystal structure of the cluster in the form (Mo3(SnCl3)S4(NCS)9)(super 6-) is isostructural with the analogous W3 compound. The distances between Mo-Mo and W-W are almost the same while those of the core Mo-S and W-S are exactly similar. The long Mo-Sn and W-Sn distances reveal any metal-metal bonding to Sn. The SnCl3 indicates a stronger bonding due to a shorter Sn-S bonds in the Mo cluster, which then implies the presence of more SnII in the W3 cube.

Reaction of the Escherichia coli R2 protein of ribonucleotide reductase (RNR) with hydrazine under anaerobic conditions yields biphasic kinetics. The first stage of reaction involves the met-R2 component of the active R2. The active protein containing the oxidising tyrosyl radical and one of the Fe(super III) centers experiences slower reduction in the second stage. Phenylhydrazine reduces the tyrosyl radical slower in a uniphasic reaction, and it is unable to reduce the Fe(super III) center. No pH-dependence is observed for this reaction.

The complexation reactions of the tetraoxo XO4 anions of molybdate(VI), tungstate(VI), vanadate(V) and arsenate(V) with the FeIIFeIII form of purple acid phosphatase from porcine uteri were investigated. Kinetic studies showed that the uniphase process give first-order constants which are independent of the tetraoxo anions. The variation in rate constants in the pH range 3.5-6.3 supported the mechanism which involves phosphatase activity.

The kinetics and thermodynamics of substitution reactions, X replacing H20 coordinated to the Ni in the cuboidal heterometallic cluster Mo3NiS4(H2O)10 (super 4+), were determined. The results showed stopped-flow formation rate constants in the range 9.44-44 M-1s-1 with X = Cl-, Br-, I- and NCS-, which are consistent with an Id dissociated interchange mechanism.

Self-exchange rate constants for rusticyanin from thiobacillus ferrooxidans were determined using proton nuclear magnetic resonance. Rusticyanin from thiobacillus ferrooxidans were compared with the other type I blue copper proteins in the 1,000 to 1,000,000 per M per seconds range. Results suggest that charge is localized on the distant regions of the molecule from the active site.

CuCl reacts with (Mo3S4(H2O)9)4+ in 2M HCl producing (Mo3CuS4(H2O)10)5+, a heterometallic cuboidal cluster. Copper turnings or CU(2+) react with (Mo3S4(H2O)9)4+ yielding (Mo3CUS4(H2O)10)4+. X-ray studies reveal the existence of the structure as an edge-linked double cube. UV-vis and EPR spectra, and kinetic studies help compare the properties of the 5+ cube and the 4+ cube.

Electrochemical studies using bis(4-pyridyl)disulfide modified gold electrode facilitate the analysis of reduction potential values of type 1 blue copper protein, pseudoazurin, from Achromobacter cycloclastes, in the pH range 3.5-8.7. Pseudoazurin has an association with reversible active site His protonation/deprotonation. NMR and kinetics studies show that active site protonation in pseudoazurin has a pKa of 4.84, which is similar to that for plastocyanin.

Analysis of the kinetics of the aconitase reactivation, involving addition of hexaqua Fe(2+), Mn(2+) and Co(2+) to Fe3S4(super 0), yields the equilibrium constants for all three processes. Reactions are studied in non-complexing sulfate and perchlorate-containing aqueous solutions at pH 7.4. These anions assist Fe(2+) to reach the active site of aconitase. Equilibrium constants are in the order of Zn(2+) greater than Co(2+) greater than Fe(2+) greater than Mn(2+).

Metalloproteins that underwent NO2 modifications at tyrosine positions provided a new method of examining intramolecular electron-transfer reactions in spinach and parsley plastocyanins. Pulse radiolysis studies were conducted to characterize and determine the molecular interactions exhibited by the compounds. Also, peptide mapping was employed in the preparation of the plastocyanin NO2 derivatives.

Substitution studies were conducted on (Mo4S4 H2O 12)4+ and (Mo4S4 H2O 12)5+. Two stages were observed for the NCS1- substitution on (Mo4S4 H2O 12)4+ with with the single (NCS1-)-dependent step requiring a statistical factor of 4, corresponding to four identical Mo(III)'s. Two (NCS1-)-dependent stages are observed for (Mo4S4 H2O 12)5+ with rate constants of 0.116/M-s for reaction at each of three Mo(III)'s and 0. 0116/M-s for reaction at Mo(IV). It is believed that there is some electron delocalization giving mobility of oxidation state and some Mo(IV) character at each Mo(III).

Further elaboration checks on earlier experiments confirmed the presence of the aqua ion product that was obtained by reacting [Mo3S4(H2O)9]4+ with Pb metal. The Pb metal reacted as a corner-shared double cube Mo6PbSsub8sup8+ and not with the single cubed Mo3PbSsub4sup4+ during the synthetic process. Analysis of the ultraviolet and visible spectra also indicated the presence of the corner-shared double cube which exhibited a distinctive spectral patterns.

Treatment of aqueous cyanide with the solid state product from molybdenum, tellurium and iodine results in the formation of (Mo3(mu(sub 2)-Te)3(CN)6)-I(sub 2.5).3H2O (3). Single X-ray crystal analysis shows that the cluster anion 3 exhibits C(sub 3v) symmetry, with 3 molybdenum atoms in equilateral triangle positions and Te(1) atom occupying the apical position. The Te-I bond length is shorter than the sum of van der Waals radii and this results in the formation of quasi-two-dimensional layers.