Molecular properties subunit structure

To be able to calculate molecular properties by additivity schemes based on contributions by structural subunits... 

Following the elucidation of the structure of the biologically active forms of Vitamin B12 in 1961, a number of enzymes have been well characterized which require B 12-coenzymes. A survey of the properties of these enzymes in terms of molecular weight, subunits and other co-factor requirements has already been published in excellent reviews by Hogenkamp (29) and Stadtman (30). 

The molecular properties of G proteins and their subunits, as well as the structural basis of the interactions among the a, p, and y subunits of G proteins and between these subunits and the associated receptor, has been immensely facilitated by X-ray crystallographic... 

Figure 31-18 Schematic representation of the subunit structure of ferritins from various tissues. (From Harrison PM, Arosh P. The ferritins molecular properties, iron storage function and cellular regulation. Biochim Biophys Acta 1996 12 75 161-203.)...

Galactose-l-P uridylyltransferase from Escherichia coli has been purified and its molecular properties characterized (29). It was found to have a M, of 80,(X)0 and to contain two subunits with a Mr of about 40,000. Active site studies showed the subunits to be functionally identical, so that it could be assumed that they are structurally identical (30). Nucleotide sequence analysis of the cloned gene gaU... 

Considerable information is available on the molecular properties of this enzyme, on the catalytic mechanism, and on the stereochemistry of the enzymic reaction. The isomerase is composed of identical associating subunits. The primary structure is known and comprises 125 residues (MW 13,394) including all the common amino acids except cysteine and tryptophan. The enzyme, which exhibits exceptionally high catalytic activity, has a molecular activity at saturating concentrations of A -androstene-3,17-dione of 4.38 X 10 min per monomer at pH 7.0 and 25°. Mechanistic studies have disclosed that the isomerase catalyzes the reaction of A < -3-ketostcroids by a direct, stercospccific, and intramolecular transfer of the 4 8-proton to the 6)8 position. There is considerable evidence for the involvement of an enolic intermediate in the... 

Bacterial bioluminescence, 30-46 factors required, 31 general scheme, 32 in vivo luminescence, 41 luminescence reaction, 37, 38 Bacterial luciferase, 33-35, 343 assay, 39 cloning, 34 crystal structure, 34 extraction and purification, 34 inactivation, 34, 35 molecular weight, 34 properties, 34 storage, 35 subunits, 34... 

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