Human platelet factor 4 subunit association/dissociation thermodynamics and kinetics

Journal Article · Tue Jul 02 00:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00240a009· OSTI ID:5013983

Chen, Mujung; Mayo, K H ^[1]

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1. Temple Univ., Philadelphia, PA (United States)

Platelet factor 4 (PF4) monomers (7,800 daltons) form dimers and tetramers in varying molar ratios under certain solution conditions. The presence of a simplified aromatic region (one Try and two His) and resolved monomer, dimer, and tetramer Y60 3,5 ring proton resonances makes study of PF4 aggregate association/dissociation thermodynamics and kinetics possible. PF4 protein subunit association/dissociation equilibrium thermodynamic parameters have been derived by {sup 1}H NMR (500 MHz) resonance line-fitting analysis of steady-state Y60 3,5 ring proton resonance monomer-dimer-tetramer populations as a function of temperature from 10 to 40 C. The thermodynamic parameters are consistent with low dielectric medium electrostatic/hydrophobic interactions governing dimer formation and hydrogen bonding governing tetramer formation. Association/dissociation kinetic parameters, i.e., steady-state jump rates, have been derived form exchange-induced linme-width increases and from {sup 1}H NMR (500 MHz) saturation-transfer and spin-lattice (T{sub 1}) relaxation experiments. From dissociation jump rates and equilibrium constants, association rate constants were estimated. Kinetically, tetramers are preferred over dimers due primarily to a slower dissociation rate, and thermo-dynamically, tetramer formation is enthalpy-driven, while dimerization is entropy-driven.

• OSTI ID: 5013983
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:26; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINO ACIDS
AROMATICS
AZOLES
BARYONS
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHEMISTRY
DIMERIZATION
ELEMENTARY PARTICLES
FERMIONS
GLYCOPROTEINS
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYDROXY ACIDS
IMIDAZOLES
KINETICS
MAGNETIC RESONANCE
MATERIALS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDES
POLYMERIZATION
PROTEINS
PROTONS
REACTION KINETICS
RELAXATION
RESONANCE
SECRETION
SPECTRA
SPIN-LATTICE RELAXATION
TEMPERATURE DEPENDENCE
THERMODYNAMICS
TYROSINE