Title
Oxygen activating nonheme iron enzymes.
Author
Lange SJ; Que L Jr
Address
Department of Chemistry Center for Metals in Biocatalysis, University of Minnesota, 207
Pleasant Street SE, Minneapolis, MN 55455, USA.
Source
Curr Opin Chem Biol, 1998 Apr, 2:2, 159-72
Abstract
The past year has witnessed significant advances in the study of oxygen-activating nonheme
iron enzymes. Thirteen crystal structures of substrate and substrate analog complexes of
protocatechuate 3, 4-dioxygenase have revealed intimate details about changes at the enzyme
active site during catalysis. Crystallographic data have established a 2-His-1-carboxylate
facial triad as a structural motif common to a number of mononuclear nonheme iron
enzymes, including isopenicillin N synthase, tyrosine hydroxylase and naphthalene
dioxygenase. The first metrical data has been obtained for the high valent intermediates Q
and X of methane monooxygenase and ribonucleotide reductase, respectively. The number
of enzymes thought to have nonheme diiron sites has been expanded to include alkene
monooxygenase from Xanthobacter strain Py2 and the membrane bound alkane
hydroxylase from Pseudomonas oleovorans (AlkB). Finally, synthetic complexes have
successfully mimicked chemistry performed by both mono- and dinuclear nonheme iron
enzymes, such as the extradiol-cleaving catechol dioxygenases, lipoxygenase, alkane and
alkene monoxygenases and fatty acid desaturases.

Title
Evidence of histidine coordination to the catalytic ferrous ion in the ring-cleaving
2,2',3-trihydroxybiphenyl dioxygenase from the dibenzofuran-degrading bacterium
Sphingomonas sp. strain RW1.
Author
Bertini I; Capozzi F; Dikiy A; Happe B; Luchinat C; Timmis KN
Address
Department of Chemistry, University of Florence, Italy.
Source
Biochem Biophys Res Commun, 1995 Oct, 215:3, 855-60
Abstract
The 1H NMR spectra of an aromatic ring-cleaving extradiol dioxygenase,
2,2',3-trihydroxybiphenyl dioxygenase of the dibenzofuran-degrading bacterium
Sphingomonas sp. strain RW1, are reported. In the catalytically active reduced form of the
monomeric enzyme (MW = 32 kDa), three broad strongly downfield shifted signals were
observed, two of which disappeared in D2O solution. Their shifts and linewidths are
consistent with ring NH and meta-like protons of coordinated histidines. These signals
show strong sensitivity to the presence of the substrate. The oxidized form of the enzyme
shows no hyperfine shifted signals. It is suggested that the high spin Fe(II) ion present in
the active form of the enzyme is coordinated by at least two histidines. This is the first report
of hyperfine shifted NMR signals being detected for an extradiol dioxygenase.

Title
Hallervorden-Spatz disease: cysteine accumulation and cysteine dioxygenase deficiency in
the globus pallidus.
Author
Perry TL; Norman MG; Yong VW; Whiting S; Crichton JU; Hansen S; Kish SJ
Address
Source
Ann Neurol, 1985 Oct, 18:4, 482-9
Abstract
We describe neurochemical abnormalities found in the brains of 2 patients with
autopsy-confirmed Hallervorden-Spatz (HS) disease. In 1 patient, contents of cystine and of
glutathione-cysteine mixed disulfide in the globus pallidus were markedly elevated above
values for appropriate control subjects. Activity of cysteine dioxygenase, which converts
cysteine to cysteine sulfinic acid, was reduced in the globus pallidus, but normal in the
frontal cortex and putamen of both patients. gamma-Aminobutyric acid content was
markedly decreased in the globus pallidus and substantia nigra of both patients. These
results suggest that cysteine accumulates locally in the globus pallidus in Hallervorden-Spatz
disease as a result of an enzymatic block in the metabolic pathway from cysteine to taurine.
Accumulated cysteine may chelate iron, accounting for the local increase in iron content in
Hallervorden-Spatz disease. The combined excess of cysteine and ferrous iron may generate
free radicals that damage neuronal membranes to cause the typical morphological changes
observed in this disorder.

Title
Purification and characterization of a cysteine dioxygenase from the yeast phase of
Histoplasma capsulatum.
Author
Kumar V; Maresca B; Sacco M; Goewert R; Kobayashi GS; Medoff G
Address
Source
Biochemistry, 1983 Feb, 22:4, 762-8
Abstract
A cysteine dioxygenase, cysteine oxidase (EC 1.13.11.20), has been purified from the
cytosolic fraction of yeast phase cells of the dimorphic fungus Histoplasma capsulatum. The
cysteine oxidase is an iron-containing dioxygenase with a molecular weight of 10500 (+/-
1500) and is present only in the yeast phase of the fungus. The enzyme is highly specific for
L-cysteine, with a Km of 2 X 10(-5) M in vitro. The product of cysteine oxidation is
cysteinesulfinic acid, as analyzed by thin-layer chromatography and mass spectroscopy. To
our knowledge, this is the first cysteine oxidase isolated from a fungus, and it probably
plays an important role in the mycelial to yeast phase transition of H. capsulatum during
which redox potential and cysteine levels are crucial factors.

Title
Pathways of cysteine metabolism in MND/ALS.
Author
Pean A; Steventon GB; Waring RH; Foster H; Sturman S; Williams AC
Address
School of Biochemistry, University of Birmingham, Edgbaston, UK.
Source
J Neurol Sci, 1994 Jul, 124 Suppl:, 59-61
Abstract
Analysis of plasma from MND/ALS patients has shown no significant differences in
metabolism of cysteine derivatives, although a sub-set of the population has raised
glutamate values. Cysteine dioxygenase was found to have reduced activity in vitro,
consistent with previous findings of a high plasma cysteine/sulphate ratio.

Title
Liver enzyme abnormalities in Parkinson's disease.
Author
Tanner CM
Address
Clinical Center for Parkinson's Disease and Movement Disorders, San Jose, California.
Source
Geriatrics, 1991 Aug, 46 Suppl 1:, 60-3
Abstract
If toxicant exposure contributes to the cause of Parkinson's disease, poor function of
detoxifying enzymes could increase vulnerability for Parkinson's disease. Although no
hepatic enzyme system has been shown universally to be dysfunctional in Parkinson's
disease patients, several have been suggested to be dysfunctional in subgroups, such as
those with young age at disease onset. Specific enzymes implicated include several P450
enzymes, most notably P450 IID6, and cysteine dioxygenase. If hepatic enzyme
abnormalities contribute to the development of Parkinson's disease, molecular genetic
techniques may allow the development of screening tests to identify at-risk subjects in order
to intervene with protective therapies.