AUTHOR
|
TITLE
|
TEXT
|
Manon Couture, Tapan Kanti Das, H. Caroline
Lee, Jack Peisach, Denis L. Rousseau,
Beatrice A. Wittenberg, Jonathan B. Wittenberg, and Michel Guertin
|
Chlamydomonas Chloroplast Ferrous Hemoglobin.
HEME POCKET STRUCTURE AND REACTIONS
WITH LIGANDS J. Biol. Chem. 1999 274:
6898-6910.
|
Experimental Procedures
Ligand Reaction Rates-- Reaction rates
were measured using a Hi-Tech model
61 (Salisbury, UK) stopped-flow apparatus
interfaced to an OLIS Data Acquisition/Computation
System (On Line Instruments Systems,
Bogart, GA). Rates were computed using
the OLIS system.
|
Stephen M. G. Duff, Jonathan B. Wittenberg, and Robert D. Hill
|
Expression, Purification, and Properties
of Recombinant Barley (Hordeum sp.)
Hemoglobin. OPTICAL SPECTRA AND REACTIONS
WITH GASEOUS LIGANDS J. Biol. Chem.
1997 272: 16746-16752.
|
Experimental Procedures
Ligand Reaction Rates
These were measured using an Hi-Tech model
SF 61 (Salisbury, UK) stopped-flow apparatus
interfaced to an OLIS Data Acquisition/Computation
System (On-Line Instrument Systems,
Bogart, GA). Rates were computed using
either the Olis system or Origins 4.1
(Microcal Software Northampton, MA).
Most kinetic experiments used Hb purified
by chromatography on Mono Q HR only,
omitting the final hydrophobic interaction
chromatography step.
|
Gang Wu, Chunhong Wei, Richard J. Kulmacz,
Yoichi Osawa, and Ah-lim Tsai
|
A Mechanistic Study of Self-inactivation
of the Peroxidase Activity in Prostaglandin
H Synthase-1
J. Biol. Chem. 1999 274: 9231-9237.
|
Experimental Procedures
Kinetics of PGHS Heme Spectral Changes
Induced by Peroxide-- Measurements were
performed on the Bio-Sequential stopped-flow
instrument in the kinetic scan-spectral
reconstruction mode or on an Olis RSM-1000
rapid-scan stopped-flow instrument (On-Line
Instrument Systems, Inc., Bogart, GA).
The former approach was used to acquire
data over shorter wavelength ranges
(typically, 390-430 nm in 2-nm increments)
and at lower enzyme concentrations.
Kinetic scan mode data obtained at serial
wavelengths were first processed by
the singular value decomposition (SVD)
method and then fitted to kinetic
models using the Glint analysis package
to deconvolute spectral intermediates.
The Olis rapid-scan instrument was used
principally to obtain spectral data
in the visible region, where a more
concentrated sample is required. Similar
SVD analysis and global fitting routines
were used to analyze data obtained with
the Olis instrument to resolve dominant
spectral intermediates and to determine
the associated reaction rate constants.
A set of published kinetic data and
a mechanistic model for the PGHS peroxide
reaction containing three spectral species
was used to validate the reliability
of the SVD/global fitting software supplied
with the Applied Photophysics and Olis
instruments and achieved an excellent
agreement.
|
Young-Lan Hyun, Zhenyu Zhu, and Victor L. Davidson
|
Gated and Ungated Electron Transfer Reactions
from Aromatic Amine Dehydrogenase to
Azurin
J. Biol. Chem. 1999 274: 29081-29086.
|
Experimental Procedures
Transient kinetic experiments were performed
using an On-Line Instrument Systems
(OLIS, Bogart GA) RSM1000 rapid-scanning
stopped-flow spectrophotometer. The
experimental procedures for the rapid
mixing experiments were as described
previously for the reactions of the
O-quinol AADH with azurin. For the reactions
of the N-quinol, it was necessary to
use anaerobic conditions. This is because
the N-quinol AADH exhibited significant
reactivity with O2, and during the incubation
times before mixing some conversion
of N-quinol to N-semiquinone occurred.
Anaerobicity was achieved by deaerating
buffers and including in the buffers
a mixture of glucose oxidase (1 unit/ml),
glucose (30 mM), and catalase (24 units/ml).
Unless otherwise indicated, reactions
were performed in 0.25 M potassium phosphate,
pH 7.5. N-Quinol AADH was prepared by
the addition of 1 M equivalent of tyramine
per TTQ. O-Quinol AADH was prepared
by titration with sodium dithionite.
Kinetic data collected in the rapid-scanning
mode were reduced by factor analysis
using Global Fit, the singular value
decomposition algorithm provided by
OLIS. Singular value decomposition-reduced
data were then globally fit by a robust
version of the Levenberg and Marquardt
(non-linear method of least squares
using the fitting routines of the Global
Fit software.
|
Kapila Ratnam, Naomasa Shiraishi, Wilbur
H. Campbell, and Russ Hille
|
Spectroscopic and Kinetic Characterization
of the Recombinant Wild-type and C242S
Mutant of the Cytochrome b Reductase Fragment of Nitrate Reductase
J. Biol. Chem. 1995 270: 24067-24072.
|
Materials and Methods
Ultraviolet/visible spectra were recorded
using a Hewlett Packard 8452A single-beam
diode array spectrophotometer; visible/near-infrared
spectra were recorded with an On-Line
Instrument Systems (OLIS) modernized
Cary-14.
Rapid mixing experiments were carried out
using a Kinetic Instruments Inc. stopped-flow
apparatus interfaced with an OLIS model
3920Z data collection system.
The kinetic transients obtained after mixing
were monitored as transmittance voltages
collected by a high speed A/D converter
and converted to absorbance changes,
and the rate constants were determined
by OLIS Inc. software.
|
Mei-Huei Jang, Jaswir Basran, Nigel S.
Scrutton, and Russ Hille
|
The Reaction of Trimethylamine Dehydrogenase
with Trimethylamine
J. Biol. Chem. 1999 274: 13147-13154.
|
Experimental Procedures
Pre-steady-state Experiments-- Kinetic
experiments were carried out using a
Kinetic Instrument Inc. stopped-flow
apparatus equipped with an On-Line Instruments
Systems (OLIS) model 3920Z data collection
system.
Kinetic transients were monitored as transmittance
voltages collected by a high speed A/D
converter and converted to absorbance
changes by OLIS software.
|
Takashi Yonetani, Antonio Tsuneshige,
Yuxiang Zhou, and Xuesi Chen
|
Electron Paramagnetic Resonance
and Oxygen Binding Studies of -Nitrosyl Hemoglobin.
A NOVEL OXYGEN CARRIER HAVING NO-ASSISTED
ALLOSTERIC FUNCTIONS
J. Biol. Chem. 1998 273: 20323-20333.
|
Experimental Procedures
Oxygen Equilibrium Measurements-- Oxygen
equilibrium curves were measured by
an improved version of Imai's automatic
method (19) with the following modifications.
Absorbance was monitored using a computer-controlled
Olis -Cary 118 spectrophotometer (Olis,
Bogart, GA).
|
Stefano Bettati, Laura D. Kwiatkowski,
Jeffrey S. Kavanaugh, Andrea Mozzarelli,
Arthur Arnone, Gian Luigi Rossi, and
Robert W. Noble
|
Structure and Oxygen Affinity of
Crystalline des-His-146 Human Hemoglobin in the T State
J. Biol. Chem. 1997 272: 33077-33084.
|
Experimental Procedures
Stopped Flow
The kinetics of combination of deoxygenated
Hb with CO were measured in an Olis stopped-flow
apparatus based on the Gibson-Durrum design
(30) as described previously (19).
Both stopped
flow studies and flash photolysis measurements
were carried out at pH 6, 7, and 8.
The buffers were prepared by titrating
an amount of HCl equal to 0.1 M chloride
with solid bis-Tris base (for pH 6 and
7) and solid Tris base (for pH 8). Inositol
hexaphosphate, IHP (Sigma), was obtained
in the sodium form. The pH of the stock
solution (0.2 M) was adjusted to pH
5.6 with the protonated form of Amberlite
IR-120 resin. IHP was added to give
a final concentration of 0.1 mM. Reactions
were followed at 420 and 435 nm, and
the temperature of the sample maintained
at 20 £¿. Data collection and processing was by
an Olis model 4000 data acquisition
and instrument control system as already
described (31). Rigorous error analysis
for the fitted rate constants is difficult.
Because of the large numbers of data
points obtained in each kinetic experiment,
the estimated errors of the fits are
very small. However, reproducibility
between and among experiments indicates
a more reasonable estimate of error
to be ?0% for the rate constants and
?5% for the fractional contributions
of the kinetic components of the reaction.
|
James T. Hazzard, Shanthi Govindaraj, Thomas
L. Poulos, and Gordon Tollin
|
Electron Transfer between the FMN and Heme
Domains of Cytochrome P450BM-3. EFFECTS
OF SUBSTRATE AND CO
J. Biol. Chem. 1997 272: 7922-7926.
|
Materials and Methods
Difference spectra were collected with
an OLIS-modified Cary 15 spectrophotometer
using the fully oxidized BM3t
as a reference spectrum.
Transient kinetic data were collected using
a Tektronix TDS 410A digitizing oscilloscope
and analyzed on a PC using KINFIT (OLIS).
|
Paul S. Kingma and Neil Osheroff
|
Spontaneous DNA Damage Stimulates Topoisomerase
II-mediated DNA Cleavage
J. Biol. Chem. 1997 272: 7488-7493.
¡¡
|
Experimental Procedures
Spectroscopic Determination of Oligonucleotide
Melting Temperatures
Ultraviolet absorbance measurements
were recorded using a modified Cary-14/OLIS
spectrophotometer (On-Line Instrument
Systems). Reaction temperatures were
controlled by a jacketed cell holder
connected to a water bath. Oligonucleotide
melting was determined by monitoring
changes in A260 as a function of temperature
over a range of 10-65 £¿. Melting curves
were derivatized incrementally and smoothed
with the software provided by the manufacturer.
The melting temperature was defined
as the temperature at which the first
order derivative of the melting curve
reached its maximum.
|
Wei Jiang and David D. Hackney
|
Monomeric Kinesin Head Domains Hydrolyze
Multiple ATP Molecules before Release
from a Microtubule
J. Biol. Chem. 1997 272: 5616-5621.
|
Materials and Methods
Stopped flow turbidity measurements were
performed with an OLIS stopped flow
spectrophotometer at 320 nm and 1.6
cm path length.
|