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H Neurath

Publications and source records attributed to H Neurath.

At least 127 records · Page 7Linked to original sources
PubMed1969

Considerations of the concept of structural homology as applied to bovine carboxypeptidases A and B.

An argument is presented in favor of the hypothesis that, bovine carboxypeptidases A and B fit by and large, the concept of homology on the levels of both amino acid sequence and three-dimensional structure. Two peptide sequences from carboxypeptidases A and B, comprising 46 amino acid residues, display structural homology to the extent of 51 per cent. One of the two peptides contains two of the amino acid residues which have been identified by X-ray crystallography as zinc ligands in carboxypeptidase A. The same residues are conserved in carboxypeptidase B in a loop of comparable dimensions. The other homologous pair of amino acid sequences appears to occur in different regions of the two enzymes which include in carboxypeptidase B the cysteinyl residue proposed to function as the third zinc ligand but not the amino acid residue believed to be the analogous ligand in carboxypeptidase A. The uncertainties of this prediction are considered in the light of existing chemical and structural evidence.

Amino Acid Sequence↗
PubMed1969

The amino acid sequence of bovine carboxypeptidase A.

The amino acid sequence of the four fragments produced by treatment of bovine carboxypeptidase A with cyanogen bromide has been completed. The alignment of these fragments, previously established by peptic digest of the whole protein, allows for the description of the complete primary structure of the molecule. A comparison of the proposed functional residues, identified by X-ray diffraction analyses, has either confirmed their assignments or provided their correct identity. The functional and structural residues of principal importance include Arg 145, Tyr 248, and Glu 270 as the binding site of the substrate carboxyl group, the proton donor, and the nucleophilic moiety, respectively, which were correctly assigned; His 196 as the third zinc ligand and Tyr 265 as the binding site of the alpha-carboxyl group have been corrected from their original X-ray assignments. The other two zinc ligands, His 69 and Glu 72, were identified previously from chemical and X-ray studies. The assignment of the two half-cystinyl residues and the postulation of the existence of a disulfide bond have been confirmed.

Amino Acid Sequence↗
PubMed1969

An immunological approach to the study of evolution of trypsins.

Antibodies were prepared in rabbits against trypsins obtained from four different species-namely bovine, porcine, spiny Pacific dogfish, and starfish (Evasterias trochelii). Each of the antisera, or the immunoglobulin G fraction thereof, was tested for its capacity to react with each of the four enzymes. The immunological reaction was assessed by three different techniques-precipitin reaction, antigen binding capacity, and inhibitory effect of the antibodies on the proteolytic activity of the enzymes. In each case, the homologous enzyme gave the strongest reaction with its antiserum but the heterologous enzymes were also capable of reacting to an appreciable extent. The cross-precipitation was the least sensitive method, and gave relatively low values, whereas cross-inhibition and cross-binding of radioactively labeled antigens indicated high extent of cross-reaction between the various trypsins. The relative capacity of interaction of the four enzymes with the four antibodies could be related to the order in which these enzymes developed during evolution. Thus the "order" of similarity was bovine > porcine > dogfish > starfish.

Animals↗