Kinetic constants in the functioning of eIF-2 and eIF-2B.
Minimum rate constants for reactions catalysed by the eukaryotic initiation factor eIF-2B in promoting formation of the ternary complex eIF-2.GTP.met-tRNAi from eIF-2.GDP are estimated from published data. The most plausible sequence of reactions in vivo is when eIF-2B remains bound to eIF-2.GTP.met-tRNA. Rate constants for reaction of eIF-2B and eIF-2.GDP are too large for protein:protein interactions at cellular concentrations in free solution. This finding suggests some form of sequestration of eIF-2 and eIF-2B in the cell to facilitate interaction, which may result in only a portion of cellular eIF-2 being actively engaged in initiation.
Department of Biochemistry, University of the Witwatersrand, Johannesburg, South Africa.
K L
KL
Manchester
D015852:Eukaryotic Initiation Factor-2; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D010448:Peptide Initiation Factors / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism*; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism
D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D011506:Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate