TY - JOUR
T1 - Time-resolved fluorescence of hemoglobin species
AU - Gryczynski, Zygmunt
AU - Beretta, Sabrina
AU - Lubkowski, Jacek
AU - Razynska, Anna
AU - Gryczynski, Ignacy
AU - Bucci, Enrico
N1 - Funding Information:
This work was supported in part by PHS grants POl-HL-485 17 and by the grants of the Center for Fluorescence Spectroscopy at the University of Maryland at Baltimore, grant NIH-RR-OS 119. Computer time and facilities were supported in part by the computer network of the University of Maryland at Baltimore, and at College Park, MD.
PY - 1997/2/28
Y1 - 1997/2/28
N2 - We used time-resolved fluorescence in the pico- to nanosecond time range to monitor the presence of tetramers, dimers and monomers in carbonmonoxyhemoglobin (COHb) solutions and to investigate how their distributions change under different experimental conditions. Comparison of fluorescence lifetime computed from the atomic coordinates of COHb (Vasquez et al., 1996) with those experimentally measured allowed identification of molecular species present in the hemoglobin solution. It was possible to observe modification of the distribution of tetramers, dimers, monomers and species with disordered hemes produced by different experimental conditions. Protein concentration affected the detectable lifetimes, indicating increasing amounts of dimers and monomers at low protein concentrations, while the amount of inverted hemes was not modified. Titration with up to 1 M NaCl modified only the extent of dissociation of hemoglobin into dimers, without affecting heme inversion and monomer formation. Hyperbaric pressure increased the amounts of dimers and monomers. This is the first time that monomeric subunits of hemoglobin have been detected at neutral pH in the normal system.
AB - We used time-resolved fluorescence in the pico- to nanosecond time range to monitor the presence of tetramers, dimers and monomers in carbonmonoxyhemoglobin (COHb) solutions and to investigate how their distributions change under different experimental conditions. Comparison of fluorescence lifetime computed from the atomic coordinates of COHb (Vasquez et al., 1996) with those experimentally measured allowed identification of molecular species present in the hemoglobin solution. It was possible to observe modification of the distribution of tetramers, dimers, monomers and species with disordered hemes produced by different experimental conditions. Protein concentration affected the detectable lifetimes, indicating increasing amounts of dimers and monomers at low protein concentrations, while the amount of inverted hemes was not modified. Titration with up to 1 M NaCl modified only the extent of dissociation of hemoglobin into dimers, without affecting heme inversion and monomer formation. Hyperbaric pressure increased the amounts of dimers and monomers. This is the first time that monomeric subunits of hemoglobin have been detected at neutral pH in the normal system.
KW - Fluorescence lifetime
KW - Hemoglobin species
KW - Time-resolved fluorescence
UR - http://www.scopus.com/inward/record.url?scp=0030892538&partnerID=8YFLogxK
U2 - 10.1016/S0301-4622(96)02224-7
DO - 10.1016/S0301-4622(96)02224-7
M3 - Article
C2 - 9127940
AN - SCOPUS:0030892538
SN - 0301-4622
VL - 64
SP - 81
EP - 91
JO - Biophysical Chemistry
JF - Biophysical Chemistry
IS - 1-3
ER -