Interactions among serum vitamin D binding protein, monomeric actin, profilin, and profilactin
JF Mc Leod, MA Kowalski, JG Haddad - Journal of Biological Chemistry, 1989 - ASBMB
Human serum vitamin D binding protein (hDBP), a 58-kDa inter-α-globulin, is known to bind,
monomeric actin (G-actin) in equimolar quantities. Using monoclonal and polyclonal anti-
hDBP antibodies, hDBP, and radioiodinated actin, we developed a reliable saturation assay
for actin bound to hDBP. By utilizing this assay, kinetic analysis, and ultracentrifugal
sedimentation in sucrose gradients, these proteins' binding affinities (K d= 10− 9 m) were
demonstrated to be 10-to 100-fold greater than earlier estimates. At 4° C, hDBP has an …
monomeric actin (G-actin) in equimolar quantities. Using monoclonal and polyclonal anti-
hDBP antibodies, hDBP, and radioiodinated actin, we developed a reliable saturation assay
for actin bound to hDBP. By utilizing this assay, kinetic analysis, and ultracentrifugal
sedimentation in sucrose gradients, these proteins' binding affinities (K d= 10− 9 m) were
demonstrated to be 10-to 100-fold greater than earlier estimates. At 4° C, hDBP has an …