The acute phase protein haptoglobin is a mammalian extracellular chaperone with an action similar to clusterin.

摘要: Haptoglobin (Hp) is an acidic glycoprotein present in most body fluids of humans and other mammals. Although the functions Hp are not yet fully understood, available evidence indicates that it likely to play important role suppressing inflammatory responses. Some earlier work suggested might be a newly identified member small group extracellular chaperones found at significant levels human fluids. Previously, only well-characterized this was clusterin, which shares functional similarities with heat-shock proteins. We report here specifically inhibited precipitation variety proteins induced by either heat or oxidation, including unfractionated serum. also show that, like (i) inhibits stressed forming solubilized high molecular weight complexes them, (ii) cannot protect enzymes from heat-induced loss function, (iii) lacks ATPase activity ability independently refold following stresses. Furthermore, we has maximum chaperone mildly alkaline pH and, unlike does undergo changes oligomerization state coincident pH-induced activity. Our results raise possibility may exert anti-inflammatory action vivo inhibiting inappropriate self-association "damaged" (misfolded)