Residual affinity

Afiinitats einheit, /. unit of affinity. kraft, /. affinity force, -lehre, /, doctrine of affinity, -rest, m. affinity residue, residual affinity, richtuDg, /. direction of affinity,... 

Once amines that also cany heteroatoms were included in the study, a dataset of 80 proton affinities was obtained. For those alkyl amines the inductive effect as quantified by residual electronegativity had also to be taken into account, A simple... 

A two-site immunometric assay of undecapeptide substance P (SP) has been developed. This assay is based on the use of two different antibodies specifically directed against the N- and C-terminal parts of the peptide (95). Affinity-purified polyclonal antibodies raised against the six amino-terminal residues of the molecule were used as capture antibodies. A monoclonal antibody directed against the carboxy terminal part of substance P (SP), covalently coupled to the enzyme acetylcholinesterase, was used as the tracer antibody. The assay is very sensitive, having a detection limit close to 3 pg/mL. The assay is fiiUy specific for SP because cross-reactivity coefficients between 0.01% were observed with other tachykinins, SP derivatives, and SP fragments. The assay can be used to measure the SP content of rat brain extracts. 

In complexes with Cro, the overall bend and twist of the DNA are similar to those in the repressor complexes, but there is a significant difference in the local structure of two of the nucleotides in each half-site. Binding of 434 Cro or repressor fragment thus imposes a distinct local structure (Figure 8.13), as a result of differences in both the identity and conformations of various amino acid residues that interact with the DNA. The DNA conformational details are significant for the relative affinities of Cro and repressor for various sites, as we describe in a later section. 

A unique feature of the interaction of the hormone and PLR is at the beginning of the F-G loop in the C-terminal domain. In HGR the sequence is Arg-Asn-Ser whereas in PLR it is Asp-His-deletion. This loop interacts with His 18 and Glu 174 of the hormone. In PLR the orientation of this loop is such that the Asp and His residues, in combination with His and Glu from the hormone, form a strong binding site for a zinc atom that links the hormone and the receptor (Figure 13.23b). The presence of zinc increases the affinity of the hormone for the receptor in vitro by a factor of 10,000. As shown by mutagenesis studies His 18 and Glu 174 of the hormone are important for the tight binding to PRL but not to GHR. 

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