Malate dehydrogenase (MDH) may be important in car-bohydrate and energymetabolism inmalarial parasites. The
cDNA corresponding to the MDHgene, identified on
chromosome 6 of thePlasmodium falciparumgenome, was
amplified by RT-PCR, cloned and overexpressed in
Escherichia coli. The recombinant PfMDH was purified
to homogeneity and biochemically characterized as an
(H)-specific MDH, which catalysed reversible inter-conversion of malate to oxaloacetate.
Human embryonic stem cells (hESCs) and induced pluripotent stem cells
are excellent models for the study of embryonic hematopoiesis in vitro,
aiding the design of new differentiation models that may be applicable to
Somatic angiotensin-converting enzyme (ACE) contains two homologous
domains, each bearing a functional active site. Studies on the selectivity of
these ACE domains towards either substrates or inhibitors have mostly
relied on the use of mutants or isolated domains of ACE.
The uptake of five fluorescein labeled cell-penetrating peptides (Tat, Tat2,
mutated-Tat, peptide vascular endothelial-cadherin and transportan) was
studied in wheat immature embryos. Interestingly, permeabilization treat-ment of the embryos with toluene⁄ethanol (1 : 20, v⁄v with permeabiliza-tion buffer) resulted in a remarkably higher uptake of cell-penetrating
peptides, whereas nonpermeabilized embryos failed to show significant cell-penetrating peptide uptake, as observed under fluorescence microscope and
by fluorimetric analysis....
Metal binding to the amyloidb-peptide is suggested to be involved in the
pathogenesis of Alzheimer’s disease. We used high-resolution NMR to
study zinc binding to amyloid b-peptide 1–40 at physiologic pH. Metal
binding induces a structural change in the peptide, which is in chemical
exchange on an intermediate rate, between the apo-form and the holo-form,
with respect to the NMR timescale.
generation is a limiting step in thyroid hormone bio-synthesis. Biochemical studies have confirmed that H2O2is
generated by a thyroid Ca
Decreased H2O2 availability may be another mechanism
of inhibition of thyroperoxidase activity produced by thio-ureylene compounds, as propylthiouracil (PTU) and
methimazole (MMI) are antioxidant agents. Therefore, we
analyzed whether PTU or MMI could scavenge H2O2or
inhibit thyroidNADPHoxidase activityin vitro.
We introduce the basic concepts and develop a theory for
nonequilibrium steady-state biochemical systems applicable
to analyzing large-scale complex isothermal reaction
networks. In terms of the stoichiometric matrix, we dem-onstrate both Kirchhoff’s flux lawR‘J‘ ¼0 over a bio-chemical species, and potential law R‘l‘ ¼0overa
reaction loop. They reflect mass and energy conservation,
The inverted repeats present in a genome play dual roles. They can induce
genomic instability and, on the other hand, regulate gene expression. In the
present study, we report the distribution and sequence features of recombi-nogenic long inverted repeats (LIRs) that are capable of forming stable
stem-loops or palindromes within the human genome.
Recent studies have suggested the existence of a novel protein of hepati-tis C virus (HCV) encoded by an ORF overlapping the core gene in the
+1 frame (core+1 ORF). Two alternative translation mechanisms have
been proposed for expression of the core+1 ORF of HCV-1a in cultured
cells; a frameshift mechanism within codons 8–11, yielding a protein known
as core+1⁄F, and⁄or translation initiation from internal codons in the
core+1 ORF, yielding a shorter protein known as core+1⁄S.
The backbone dynamics of the
N-labeled homeodomain of the rat thy-roid transcription factor 1 has been studied by 2D NMR spectroscopy.
) and transverse (R2
N relaxation rate constants and
N NOEs were measured at 11.7 T.
Mammalian adenylate cyclases are predicted to possess
complex topologies, comprising two cassettes of six trans-membrane-spanningmotifs followedbyacytosolic, catalytic
ATP-binding domain. Recent studies have begun to provide
insights on the tertiary assembly of these proteins; crystal-lographic analysis has revealed that the two cytosolic
domains dimerize to forma catalytic core, whilemore recent
biochemical and cell biological analysis shows that the two
transmembrane cassettes also associate to facilitate the
functional assembly and trackingof the enzyme. ...
The characterization of the gene encodingLeishmania
donovaniphosphofructokinase (PFK) and the biochemical
properties of the expressedenzyme are reported.L. donovani
has a singlePFKgene copyperhaploidgenome that encodes
a polypeptide with a deducedmolecular mass of 53 988 and
a pI of 9.26. The predicted amino acid sequence contains a
C-terminal tripeptide that conforms to an established signal
for glycosome targeting.
In order to study the pressure-induced changes of biological
membrane, hydrostatic pressures of from 0.1 to 400 MPa
were applied to membrane-bound Na
pigkidneyas amodel systemof proteinand lipidmembrane.
The activity showed at least a three-step change induced by
pressures of 0.1±100 MPa, 100±220 MPa, and 220 MPa or
Physiological and biochemical responses induced by salt stress were studied in laboratory-grown young plants of the mangrove, Bruguiera gymnorrhiza. The growth rates and leaf areas were highest in the culture with 125 mM NaCl. Transpiration rates showed a diel periodicity when the plants were placed in water, but the oscillatory cycles disappeared for plants placed in higher
Candida albicansexo-b-1,3-glucanase (Exg; EC 184.108.40.206) is implicated in
cell wall b-d-glucan remodelling through its glucosyl hydrolase and⁄or
transglucosylase activities. A pair of antiparallel phenylalanyl residues
(F144 and F258) flank the entrance to the active site pocket. Various Exg
mutants were studied using steady-state kinetics and crystallography aiming
to understand the roles played by these residues in positioning the b-1,3-d-glucan substrate.
Flavonols are produced by the desaturation of flavanols
catalyzed by flavonol synthase. The enzyme belongs to the
class of intermolecular dioxygenases which depend on
molecular oxygen and Fe
/2-oxoglutarate for activity, and
have been in focus of structural studies recently. Flavonol
synthase cDNAs were cloned from six plant species, but
none of the enzymes had been studied in detail.
Aldo-keto reductase 1B1 and 1B3 (AKR1B1 and AKR1B3) are the pri-mary human and mouse prostaglandin F2a(PGF2a) synthases, respectively,
which catalyze the NADPH-dependent reduction of PGH2, a common
intermediate of various prostanoids, to form PGF2a. In this study, we
found that AKR1B1 and AKR1B3, but not AKR1B7 and AKR1C3, also
catalyzed the isomerization of PGH2 to PGD2 in the absence of NADPH
The well studied bacterial tyrosinases from theStreptomycessp. bacteria
are distinguishable from their eukaryotic counterparts by the absence of a
C-terminal extension. In the present study, we report that the tyrosinase
from the bacterium Verrucomicrobium spinosumalso has such a C-terminal
extension, thus making it distinct from the Streptomycesenzymes.
A novel plant protein isolated from the underground bulbs of
Scadoxus multiflorus, xylanase and a-amylase inhibitor protein (XAIP),
inhibits two structurally and functionally unrelated enzymes: xylanase and
a-amylase. The mature protein contains 272 amino acid residues which
show sequence identities of 48% to the plant chitinase hevamine and 36%
to xylanase inhibitor protein-I, a double-headed inhibitor of GH10 and
Ammonium assimilation is tightly regulated in nitrogen-fixing bacteria; the
target of regulation is primarily the activity of the key enzyme glutamine
synthetase that is regulated by reversible covalent modification by AMP
groups in reactions catalysed by the bifunctional adenylyltransferase
(ATase). The properties and regulation of ATase fromEscherichia colihave
been studied in great detail.