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D Beale

Publications and source records attributed to D Beale.

At least 55 records · Page 3Linked to original sources
PubMed1985

A comparison of the amino acid sequences of the extracellular domains of the immunoglobulin superfamily. Possible correlations between conservancy and conformation.

Amino acid sequences of immunoglobulins, histocompatibility antigens, Thy-1 antigens, polyimmunoglobulin receptor and T-lymphocyte receptor have been compared and conserved residues correlated with features on the atomic models of immunoglobulin fragments. The peptide chains are apparently folded into globular domains closely related in three-dimensional structure to immunoglobulin V or C domains. Exceptions are histocompatibility class I alpha 2 and class II beta 1 domains, distantly related, and class I and II alpha 1 domains, no apparent relationship to immunoglobulin domains.

Amino Acid Sequence↗
PubMed1984

Construction and characterization of a plasmid containing complementary DNA to mRNA encoding the N-terminal amino acid sequence of the rat glutathione transferase Ya subunit.

Free polyribosomal poly(A)-containing RNA isolated from normal rat liver was used to prepare a complementary DNA plasmid library in the Pst1 site of the plasmid pAT153 . A plasmid pGSTr155 complementary to mRNA coding for a glutathione transferase Ya subunit was selected by differential hybridization in situ and preliminary characterization was performed by hybrid-selected mRNA translation, immunoprecipitation and polyacrylamide-gel electrophoresis of the product synthesized in vitro. The nucleotide sequence of the complementary DNA contained within pGSTr155 was determined and shown to contain a single open reading frame corresponding to the first 129 amino acids of the N-terminus of the Ya subunit and a further 63 nucleotides upstream of the initiating methionine codon.

Amino Acid Sequence↗
PubMed1983

Evidence that the Yb subunits of hepatic glutathione transferases represent two different but related families of polypeptides.

Three soluble rat liver glutathione (GSH) transferases A, C and one referred to as 'D', all of which are dimers of Yb subunits [Bass et al. (1977) Biochim. Biophys. Acta, 492, 163-175], have been compared with respect to C-terminal amino acids and tryptic peptide maps. GSH transferases A and 'D' gave different tryptic peptide maps and different C-terminal amino acids, lysine and proline respectively. In each case the number of tryptic peptides is about half of that expected from their lysine and arginine content, and there are 2 mol C-terminal amino acid/mol enzyme. This indicates that GSH transferases A and 'D' represent two different Yb homodimers, which we refer to here as Y1bY1b and Y2bY2b respectively. GSH transferase C is the corresponding heterodimer Y1bY2b since it gives all the tryptic peptides which arise from GSH transferase A and GSH transferase 'D' and also contains both C-terminal lysine and proline. These results provide a structural basis to similar conclusions drawn by Mannervik and Jensson [(1980) J. Biol. Chem. 257, 9909-9912] based on enzymic and immunological comparisons. Tryptic peptide maps show that GSH transferases A and 'D' have considerable homology since there are 23 peptides common to both, 12 peptides unique to A and 8 peptides unique to 'D'. Even so GSH transferase A is selectively induced by a phenobarbitone regime. It is, therefore, concluded that Y1b and Y2b are derived from separate but related genes. A similar conclusion has been drawn concerning the Ya and Yc subunits [Beale et al. (1982) Eur. J. Biochem. 126, 459-463], and a comparison of amino acid compositions, presented here, further suggests a genetic relationship between both pairs of subunits.

Amino Acids↗
PubMed1983

A comparison of the fragmentation of different species of mammalian immunoglobulin M by trypsin in urea.

Six different species of mammalian IgM that had been preincubated in 4-6 M urea showed marked differences in their fragmentation by trypsin at 25 degrees C. These differences are most probably due to different degrees of conformational change in urea particularly as regards the C mu 2 domains. The fragments obtained by digestion with trypsin in urea were often different to those obtained by digestion in aqueous buffer at 37 or 55 degrees C. In particular the production of (Fc*)5 fragment containing C mu 2 domains was favoured. In the case of human and mouse IgM the fragmentation could be controlled sufficiently to produce series of molecules which differed in their numbers of Fab arms and/or C mu 2 domains.

Animals↗
PubMed1982

Evidence that the Ya and Yc subunits of glutathione transferase B (ligandin) are the products of separate genes.

A study of the structure of glutathione transferase B (ligandin) has been made with a view to understanding the relationship between the structures of the subunits of which it is composed. It consists of a mixture of a homodimer (YaYa) and a heterodimer (YaYc) in which the monomers are defined by their apparent molecular weights, that of Ya being 22000 and Yc 25000. Soluble tryptic peptides from the native homodimer YaYa have been compared with those from an artificial homodimer YcYc produced by rehybridization of native YaYc. Approximately 10 peptides specific to YaYa, 12 specific to YcYc and 21 common to both have been detected. Some of the above peptides are derived from variants of the monomers themselves. YaYa and YcYc have two C termini which are the same in both dimers, namely phenylalanine and lysine. Also there are four cysteinyl peptides, of which three are common to YaYa and YcYc and one specific to each. These results suggest that Ya and Yc are derived from at least two different but related genes.

Chemical Phenomena↗
PubMed1982

The limited fragmentation of porcine haemolytic immunoglobulin M. Evidence that haemolytic activity depends on the number of Fab arms that can attach to the erythrocyte surface.

Methods previously developed in this laboratory for the proteolytic removal of limited numbers of Fab arms from the IgM molecule have been used to study haemolytic activity. The gradual removal of arms produced a rapid decrease in complement-mediated lysis of erythrocytes but had a much slower effect on their agglutination. Therefore a stage was reached at which molecules with four Fab arms gave good agglutination but did not cause cell lysis. The same result was obtained whether Fab arms were removed randomly by pepsin or in pairs by trypsin. Hence the non-lytic nature of these molecules was independent of the arrangement of their remaining Fab arms. A sharp decrease in haemolytic activity was also obtained under conditions of high antibody concentration when the IgM molecular could attach only a few of its Fab arms to the erythrocyte surface. Possible explanations for the dependence of haemolytic activity on the number of Fab arms discussed.

Animals↗
PubMed1982

A comparison of the proteolytic fragmentation of immunoglobulin M from several different mammalian species.

1. IgM from six different mammalian species was fragmented with three different proteases. 2. Differences occurred in the proteolysis of the same domain of different species and different domains of the same species. 3. The inter-chain disulphide bridge in the C mu2 domain moderated the nature of the fragments. 4. No well defined polymeric fragment lacking the C mu2 disulphide bridge was obtained. 5. Only in a few cases did fragmentation proceed in regular steps and produce a well defined series of partially fragmented molecules.

Animals↗
PubMed1981

A comparison of the actions of trypsin and pepsin on porcine immunoglobulin M and their effects on biological activity.

The action of trypsin at 55 degree C and pH 8.3 on pig IgM anti-Salmonella has been compared with the action of pepsin at 37 degree C and pH 4.6. Both processes cause the gradual removal of Fab arms and Cmu2 domains to produce eventually an (Fc)5 fragment. However, during tryptic digestion Fab arms are preferentially removed from the same subunit, whereas peptic digestion causes random removal from any subunit. At intermediate stages of digestion both processes produce partially fragmented molecules which consist of an (Fc)5 portion still attached to limited numbers of Fab arms. Both processes cause a gradual decrease in the ability of molecules to agglutinate Salmonella, but complement fixation by the complexes declines much more rapidly. A stage is reached where molecules having four Fab arms can still agglutinate but there is no complement fixation. However, the remaining arms on the tryptic molecules are distributed in pairs on the same subunit, whereas those on the peptic molecules are distributed randomly. Hence the number of remaining Fab arms, rather than their distribution, appears to be the critical factor which influences biological activity. A possible explanation for this is discussed.

Agglutination↗
PubMed1980

The action of pepsin on porcine immunoglobulin M and its effect on biological activity.

Treatment of porcine immunoglobulin M (IgM) with pepsin at pH 4.6 and 37 degrees C was found to gradually remove Fab arms and Cmicro2 domains over a period of 18h. Structural studies failed to find any other change. The main products can therefore be regarded as IgM-like molecules with limited numbers of Fab arms and Cmicro2 domains. Results indicated that this removal of Fab arms is probably a random process. As the average number of Fab arms per molecule was decreased the ability to agglutinate Salmonella oranienburg (mt-H) gradually diminished. Complement fixation by the complexes however, decreased rapidly, and became negligible when the average number of Fab arms was four. This was confirmed by using a preparation containing mainly molecules with three or four Fab arms. The overall results showed that molecules with three or four Fab arms can agglutinate Salmonella but that these complexes do not fix complement. Molecules with five arms probably behave like those with four. Complexes formed by molecules with six arms fix complement quite efficiently. Possible explanations for these results are discussed.

Agglutination↗
PubMed1978

The effect of limited fragmentation of porcine 19 S IgM on agglutination and complement fixation. Evidence that at least two intact subunits are required for complement fixation by IgM antibody.antigen complexes.

Limited fragmentation of pig IgM anti-Salmonella with pepsin gave a 12 S product which agglutinated Salmonella almost as efficiently as the original IgM but the complement fixing ability of the complexes was substantially lowered. The 12 S product was shown to consist of molecular entities having intact Fc regions with an average of 3 or 4 intact Fab arms still attached. Our results appeared to show that removal of Fab arms by pepsin was a random process and on this basis a mathematical model was set up. From this model it was possible to calculate the frequencies of molecular entities which would give rise to the observed average of 3 or 4 Fab arms. The most likely explanation of our results is that complexes need to be formed by molecules having at least two intact subunits before efficient complement fixation takes place.

Animals↗
PubMed1977

Radio telemetry of intraocular pressure in vitro.

A guard ring pressure transensor, using the principles of surface applanation, was used to transmit intraocular pressure (IOP) from a cadaver canine eye. The transensor consisted of a passive resonant coil/capacitor combination, made pressure sensitive by the movement of a small ferrite plate which acted as its applanating surface. Oscillation induced in the transensor by a remote grid dip oscillator (GDO) was monitored by a digital frequency counter (DFC). The resonant frequency of oscillation in the transensor bore a linear relationship to the in vitro IOP in three separate experiments (coefficient of determination for linear regression, r2 equals 0.90). These data indicate that radio telemetry is feasible, using a miniature applanating passive radio telemetric device for continual monitoring of IOP.

Animals↗
PubMed1976

A low-molecular-weight protein from rat liver that resembles ligandin in its binding properties.

A protein of S20,W 1.6S and mol.wt. 14000, which binds covalently a metabolite of the aminoazodye carcinogen NN-dimethyl-4-amino-3'-methylazobenzene, was isolated from rat liver cytosol from both carcinogen-treated and normal rats. The protein binds non-covalently palmitoyl-CoA, fatty acids, bilirubin, sex steroids and their sulphates, bile acids and salts, bromosulphophthalein, diethylstilboestrol and 20-methylcholanthrene with a wide range of affinities. The protein is isolated as three components with isoelectric points of 5.0, 5.9 and 7.6 by a method involving isoelectric focusing. All three components have closely similar amino acid analyses, tryptic-peptide 'maps' and u.v. spectra. Each single component redistributes into all three on further electrophoresis. However, the three forms differ in their binding characteristics, the form of pI 7.6 having much the highest affinity for compounds bound non-covalently. The protein was identified immunologically in rat liver, small intestine, adipose tissue, skeletal muscle, myocardium and testis. The protein was compared with other hepatic binding-protein preparations of similar molecular weight.

Amino Acids↗