Cyclic tetramolecular complexes of monoclonal antibodies: a new type of cross-linking reagent.

A simple and efficient procedure for the construction of bifunctional molecules is described and their use in a variety of applications documented. This procedure is based on our observation that mouse IgG1 monoclonal antibodies, when mixed with equimolar amounts of a high-affinity rat monoclonal antibody specific for mouse IgG1, yield uniform cyclic tetramolecular complexes each consisting of two mouse and two rat antibodies as shown by gel electrophoresis and electron microscopy. When solutions of two mouse antibodies (e.

The alpha-macroglobulins from rat plasma: structure, plasma clearance and endocytosis of complexes with subtilisin.

Rat alpha 2M was isolated from plasma of animals which had been treated with stress hormones. Polyacrylamide-gel electrophoresis of the reduced protein in the presence of sodium dodecyl sulfate showed a band with a Mr of 175,000. In a previous work (Biochem.

Complexes of rat alpha 1-macroglobulin and subtilisin are endocytosed by parenchymal liver cells.

Rat alpha 1-macroglobulin was isolated from plasma. Gel electrophoresis of the denatured and reduced protein showed two bands, with Mr values of 163 000 and 37 000. The large subunit contained an autolytic site.

The quaternary structure of Escherichia coli RNA polymerase studied with (scanning) transmission (immuno)electron microscopy.

A model for the quaternary structure of Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.

Hemocyanins in spiders, XV. The role of the individual subunits in the assembly of Eurypelma hemocyanin.

The role of the seven different subunits in the quaternary structure of the 24-meric (37 S) hemocyanin of the tarantula, Eurypelma californicum, was studied by reassembly experiments. Individual subunits and combinations of 2, 3, 4, etc. different subunits were incubated in a total concentration of 1-2 mg/ml overnight in Tris buffer, pH 7.

On the role of dimeric subunits in the quaternary structure of arthropod hemocyanins.

Partial alkaline dissociation of 24 S (12-meric), 35 S (24-meric) and 60 S (48-meric) hemocyanin from various arthropods was studied by polyacrylamide gradient gel electrophoresis and, in some cases, by electron microscopy. If there are no stable dimers among the subunits, dissociation starts by cleavage of interhexamer bonds, leading to intermediates which are hexamers or multiples of hexamers. Whenever a hemocyanin contained stable dimers, inter-hexamer bonds were also very stable as indicated by the formation of 30 S (19-meric) or 18 S (7-eric) intermediates as primary products.