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M W Hatton

Publications and source records attributed to M W Hatton.

At least 91 records · Page 5Linked to original sources
PubMed1977

Bovine serum transferrin phenotypes AA, D1D1, D2D2, EE: their carbohydrate compositions and electrophoretic multiplicity.

Samples of homozygous bovine serum transferrins have been prepared and their purity has been ascertained by immunological techniques and electrophoretic analysis in SDS. Measurements of carbohydrate composition show that no significant differences exist among the phenotype variants AA, D1D1, D2D2, and EE. Chromatography of transferrin AA on DEAE-cellulose separated four subfractions, each of which corresponded well with one band obtained by polyacrylamide gel electrophoresis. Carbohydrate analyses of the individual subfractions did not show significant differences in sialic acid, hexose, or hexosamine contents. After desialylation with neuraminidase, each subfraction was converted to a major band and a minor band on gel electrophoresis. From the relative band positions of the desialylated transferrins, it was concluded that possession of sialyl residued by bovine transferrin is not the primary cause of electrophoretic multiplicity. Rather, sialic acid masks an underlying heterogeneity which most likely resides within the polypeptide chain. Further characterization of this heterogeneity will best be undertaken with the isolated asialotransferrin subfractions.

Animals↗
PubMed1977

The molecular components of human transferrin type C.

Immunologically pure human transferrin type C (TfC) was isolated from the plasmas of 11 individual healthy donors. After conversion into the 2Fe-form, the preparations were analysed by polyacrylamide gel electrophoresis and chromatography on DEAE-cellulose. In all samples studied by either method the presence of three components, designated A, B and C, was observed. Calculations from eight chromatograms yielded the following relative proportions for the components: A:6%, B:62% and C:32%. The quantity of iron bound played no role in this chromatographic resolution. The components were immunologically identical but their sialic acid content increased inthe order of A less than B less than C. The presence of galactose as an ultimate residue of the oligosaccharide chains in TfC component A was confirmed by a biological test. This observation together with the results of earlier analyses for hexose, hexosamine and galactose in the subfractions from Behringwerke human transferrin, suggests that sialic acid is probably the only variable among TfC components A, B and C. Loss of sialic acid from component C during the isolation of TfC was excluded as an explanation for the presence of the other two components. The electrophoretic appearance of TfC samples from five patients with liver disease (chronic active hepatitis, cirrhosis or alcoholic liver) did not noticeably differ from that of TfC FROM HEALTHY PERSONS. Baboon transferrin resembles TfC with respect to sialic acid heterogeneity. This species was therefore studied to decide whether sialic acid is gradually lost from transferrin in the circulation or whether transferrin is not fully sialylated before discharge from the hepatocyte. Using DEAE-cellulose chromatography no difference was found between baboon transferrin molecules which were less than 6h old and those which had a mean age of 8.9 days. By inference it is suggested that the reason for the multiplicity of TfC is also likely to be biosynthetic.

Adult↗
PubMed1976

The physicochemical and chemical properties of alpha 1-acid glycoproteins from mammalian and avian plasmas.

We have isolated from the plasma of man, rabbit, pig, rat and chicken alpha 1-acid glycoproteins that show a single band on polyacrylamide gel electrophoresis and a single arc in immunodiffusion. Amino acid and carbohydrate compositions are presented. The human protein is very similar to preparations described by earlier workers and, although significant differences in amino acid composition exist among them, the proteins from the other species are assumed to be analogous to it. Ultra centrifugal studies, despite showing single, fairly symmetrical peaks at high speed, produced evidence for the physical heterogeneity of each protein in agreement with some earlier reports. Although many models consisting of mixtures of components were tested, none was found that fitted adequately all observations on any one of the glycoproteins.

Amino Acids↗
PubMed1976

The proteolytic nature of commercial samples of galactose oxidase. Purification of the enzyme by a simple affinity method.

Several commercially available samples of galactose oxidase (D-galactose: oxygen 6-oxidoreductase, EC 1.1.3.9) were found to contain high proteolytic activity on proteins such as fibrinogen, transferrin, albumin and casein. A simple, efficient method was devised for the purification of galactose oxidase which relies on the affinity of the enzyme for agarose (Sepharose 6B). The purified galactose oxidase was recovered in high yield free from proteolytic activity. The enzymic affinity for Sepharose and Sephadex was investigated to clarify the absorption mechanism.

Alcohol Oxidoreductases↗
PubMed1976

The affinity of human, rabbit and bovine thrombins for sepharose-lysine and other conjugates.

Human, rabbit and bovine thrombins are shown to possess marked affinities for Sepharose-lysine. Using either Xa-activated crude prothrombins (human, rabbit) or a commercial thrombin sample (bovine), the enzyme was isolated in a single chromatographic step by the affinity medium and preparations of high specific activity were obtained. The relevance of bound-lysine for the affinity of the thrombins was studied using other Sepharose conjugates with structures related to Sepharose-lysine. Using freshly activated prothrombins it was found that human and rabbit thrombin uptake required a conjugate with a spacer chain containing a minimum of four carbon atoms in length which supported a terminal amino group. As the thrombin activity aged, affinity for the terminal amino group decreased but the hydrophobic spacer chain became essential for enzyme binding. The active centre of thrombin was not involved in binding to Sepharose-lysine.

Animals↗
PubMed1976

Studies of the metabolism of asialotransferrins: nonspecific changes in the metabolic behaviour of human asialotransferrin in avians.

In a previous study (Regoeczi, E. & Hatton, M.W.C. (1976) Can J. Physiol. Pharmacol. 54, 27-34) it was shown that the chicken (Gallus domesticus) does not possess a hepatic asialoglycoprotein receptor. In the present study the same conclusion is drawn for the duck (Anas platyrhynchos). For this reason these avian species were used to assess those changes in the distribution and catabolism of human asialotransferrin which takes place in the absence of the asialoglycoprotein receptor of the liver.

Animals↗
PubMed1976

Asialoglycoprotein clearance in the chicken: evidence for the lack of a hepatic asialoglycoprotein receptor.

The behaviour of desialylated human and chicken acid alpha1-glycoproteins is reported in chickens. Although desialylation resulted in accelerated disappearance rates from the plasma of both proteins, nevertheless the asialoproteins were eliminated much more slowly than expected on the basis of earlier observations in mammals. Analysis of tissue radioactivities, including kidney, liver, lung and spleen, failed to demonstrate any accumulation of the labeled asialoproteins in the liver, which is contrary to the situation in mammals. The main pathway for the elimination of desialylated human acid alpha1-glycoprotein in the chicken is via the kidney (tubular catabolism and/or urinary excretion). The clearance of desialylated chicken acid alpha1-glycoprotein is more complex as it involves the kidney as well as the reticuloendothelial system. These findings indicate that, unlike mammals, chickens do not possess a hepatic plasma membrane receptor for asialoglycoproteins. This raises the possibility that the presence or absence of this specific receptor may constitute a fundamental biological difference between mammals and birds.

Animals↗
PubMed1975

The effect of heparin on the affinity chromatography of plasminogen. Demonstration of heparin-plasminogen interaction.

Evidence is presented that heparin binds rabbit plasminogen types I and II under affinity chromatographic conditions using the single stage technique earlier described (Hatton, M.W.C. and Regoeczi, E. (1974) Biochim. Biophys. Acta 359, 55-65). Thus, the affinity of types I and II for Sepharose-lysine is markedly increased in the presence of heparin and elution by epsilon-aminohexanoic acid requires a steeper gradient to recover the plasminogen types. Furthermore by adding sufficient epsilon-aminohexanoic acid to non-heparinised plasma to suppress plasminogen affinity, the presence of heparin is shown to encourage binding of plasminogen (type II more so than type I) to the gel. However, the heparin effect is quickly reversed by washing the column with 0.5 M NaCl prior to elution by epsilon-aminohexanoic acid. No evidence of a stable plasminogen-heparin complex has been found from gel filtration studies and any interaction between plasminogen and heparin probably only takes place when heparin is bound to an affinity site. Studies with 35-S-labelled heparin have shown the mucopolysaccharide to bind to the free amino group of Sepharose-lysine and Sepharose-cadaverine and to be displaced by 0.5 M NaCl elution but not by 0.1 M epsilon-aminohexanoic acid. The plasminogen types produced from heparinised plasma are free from heparin and closely resemble preparations from non-heparinised plasma when compared by polyacrylamide gel electrophoresis, Sephadex gel filtration and arginine esterase activity after urokinase activation.

Aminocaproates↗
PubMed1975

The relevance of the structure of lysine bound to Sepharose for the affinity of rabbit plasminogen;.

The features of the structure of lysine, linked to Sepharose by the alpha-amino group, which are important for affinity chromatography of rabbit plasminogem were studied. Nine lysine and lysine-like conjugates, including epsilon-aminohexanoic acid DL-norleucine, DL-alpha-aminoadipic acid, DL-alpha-epsilon-diaminopimelic acid, cadaverine L-ornithine, L-arginine and D-lysine, were prepared; Using labelled rabbit plasminogen added to plasma, the ability of each conjugate to absorb plasminogen and separate the allomeric forms, type I and type II, during epsilon-aminohexanoic acid gradient elution was compared to Sepharose-L-lysine. Plasminogen had no affinity for Sepharose-epsilon-aminohexanoic acid, and was only weakly attracted by Sepharose-norleucine, Sepharose-cadaverine and others. Sepharose-ornithine held a greater attraction to the protein but the strongest binding was obtained with Sepharose-arginine. The affinity of plasminogen type I was always less than type II for the Sepharose-lysine analogues and the recovery of type II greater than type I from Sepharose-ornithine and Sepharose-arginine. Plasminogen affinity was in the order of Sepharose-arginine greater than Sepharose-lysine greater than Sepharose-ornithine. However, because of the present difficulty in recovering plasminogen from Sepharose-arginine the use of Sepharose-lysine in the affinity chromatography of rabbit plasminogen remains unchallenged. It is concluded that binding of rabbit plasminogen to conjugates of lysine and its analogues is determined by the presence of both a free carboxyl and a free amino group and that the distance between these groups is critical.

Animals↗
PubMed1975

Studies of the metabolism of asialotransferrins: the metabolic heterogeneity of human asialotransferrin.

Catabolism of human transferrin and human asialotransferrin was simultaneously studied in guinea pigs by means of total body radioactivity measurements. Total body activity representing transferrin decreased at a constant rate with an average half-life of 88 h. Decrease of the total body activity representing asialotransferrin exhibited at least two rates; the half-life of the fast initial component averaged at 25 h, whereas the half-life of the slower component averaged at 55 h. Transition occurred between the 50th and 80th hours of the experiments. The complex character of the elimination curves could not be explained by differences in the iron content of asialotransferrin, by the presence of transferrin variants or of denatured protein in the injected material, by residual sialic acid in the preparations, by accumulation of radioactive terminal catabolic products in the body, by an association of asialotransferrin with any other macromolecular plasma constituent, by changing conditions for mass action, or by a continuing return of labeled protein from the extravascular space. Injection of bovine asialotransferrin into guinea pigs did not result in complex total body curves. Analyses of guinea pig tissues demonstrated that human asialotransferrin had marked affinity for the liver and none for the kidney, lung, or spleen. These observations are consistent with the hypothesis that the glycopeptides in human transferrin are heterogeneous in that removal of the sialyl residues exposes structures with different affinities for the hepatic asialoglycoprotein receptor. The precise chemical basis for the metabolic heterogeneity is unknown.

Animals↗
PubMed1975

Studies of the metabolism of asialotrasferrins: the in vivo behavior of baboon and rhesus asialotransferrins.

The catabolism and distribution of rhesus and baboon asialotransferrins relative to the corresponding parent proteins were studied in rabbits using a dual isotope tracer technique. Also a similar study with the baboon proteins in a baboon is reported. The metabolic data obtained in rabbits with both rhesus and baboon transferrins was close to the values established in a previous study for rabbit transferrin. Desialylation resulted in an average increase in the fractional catabolic rate of rhesus trasferrin by 22.7%. This change is similar to that found earlier with asialotransferrins from several nonprimate mammals which are thought not to interact with the hepatic asialoglyco-protein receptor. Two kinetically distinct fractions were identified in baboon asialotransferrin. One of these, amounting to approximately one-third of the protein, was eliminated from the circulation very rapidly. The remaining two-thirds constituted a slowly catabolized fraction which behaved in vivo similarly to rhesus asialotransferrin. Unlike the rapidly cleared fraction, elimination of the slowly catabolized fraction in baboon asialotransferrin is probably not mediated by the hepatic asialoglycoprotein receptor. An amount comparable to the rapidly eliminated fraction in baboon asialotransferrin was recovered with the liver of rats in short-term experiments. In rats which were preinjected with chicken acid alpha1-glycoprotein the hepatic uptake of baboon asialotransferrin was markedly reduced. Data obtained in the baboon agreed with the findings in rabbits, although transferrin turnover was slower in the baboon. From its behavior in vivo as an asialoglycoprotein, baboon transferrin shows greater resemblance to human transferrin than rhesus transferrin. The conclusion is supported by carbohydrate analyses which show an intermediate position for baboon transferrin between man and a nonprimate mammal (rabbit), and a similarity between rhesus and rabbit transferrins.

Animals↗