Reactivity of ferrate(VI) and ferrate(V) with amino acids

Journal Article · Wed Nov 13 04:00:00 EST 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00023a005· OSTI ID:7265906

Sharma, V K; Bielski, B H.J. ^[1]

---

1. Brookhaven National Lab., Upton, NY (United States)

The oxidation of the essential amino acids by ferrate(VI) (Fe(VI)) and ferrate(V) (Fe(V)) has been studied by stopped-flow and pulse radiolysis techniques at pH 12.4 and 23-24C. FeO{sub 4}{sup 3{minus}} was formed in these studies by reduction of Fe(VI) with radiation-generated reducing radicals. Both Fe(VI) and Fe(V) react preferentially with amino acids in which the {alpha}-amino group is protonated (RCH(NH{sub 3}{sup +})COO{sup {minus}}). Rate constants (k{sub 5}) for reaction of Fe(VI) with RCH(NH{sub 3}{sup +})COO{sup {minus}} range from 10 to 10{sup 3} M{sup {minus}1} s{sup {minus}1}. The corresponding k{sub 6} values for Fe(V) are orders of magnitude higher: k{sub 6} = (0.01-5.0) {times} 10{sup 7} M{sup {minus}1} s{sup {minus}1}. Cysteine, a reducing species, reacts with Fe(VI) at a rate of d = 760 {plus minus} 49 M{sup {minus}1} s{sup {minus}1} and with FeO{sub 4}{sup 3{minus}} at a nearly diffusion-controlled rate of k = (4.0 {plus minus} 0.8) {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}; both rates were computed on the basis of (cysteine){sub tot}. The ratio k{sub 6}/k{sub 5} varies from 5 {times} 10{sup 3} to 3 {times} 10{sup 5}; for cysteine this ratio is 5 {times} 10{sup 6}. The oxidation process of amino acids initiated by Fe(V) proceeds in presence of Fe(VI) by a chain reaction in which amino acid free radicals and Fe(V) are the chain carriers.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7265906
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 30:23; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALANINES
AMBIENT TEMPERATURE
AMIDES
AMINES
AMINO ACIDS
ARGININE
AROMATICS
ASPARAGINE
AZAARENES
AZOLES
CARBOXYLIC ACIDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CYSTEINE
CYSTINE
DECOMPOSITION
DISULFIDES
DRUGS
FERRATES
GLUTAMINE
GLYCINE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYDROXY ACIDS
IMIDAZOLES
INDOLES
IRON COMPOUNDS
KINETICS
LEUCINE
LIPOTROPIC FACTORS
LYSINE
METHIONINE
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PH VALUE
PHENYLALANINE
PROLINE
PYRROLES
PYRROLIDINES
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION KINETICS
REDUCTION
SERINE
THIOLS
THREONINE
TRANSITION ELEMENT COMPOUNDS
TRYPTOPHAN
TYROSINE