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Biomedical subjects

W T Butler

Publications and source records attributed to W T Butler.

At least 127 records · Page 7Linked to original sources
PubMed1977

Proteins of the periodontium. Characterization of the insoluble collagens of bovine dental cementum.

Cyanogen bromide (CNBr) peptides were prepared of the insoluble collagen of bovine dental cementum. Following chromatographic separation, the peptides were identified by their amino-acid composition. Type I collagen ([alpha1(I)]2alpha2) accounted for more than 90% of the organic matrix, while Type III collagen ([alpha1(III)]3) was present at a level of approximately 5%. Amino-acid analyses revealed that the CNBr peptides from alpha1(I) and alpha2 chains of cementum closely resembled the corresponding peptides from calf skin. The only systematic difference was a higher level of hydroxylation of prolyl and lysyl residues of the cementum peptides.

Amino Acids↗
PubMed1977

The covalent structure of cartilage collagen. Evidence for sequence heterogeneity of bovine alpha1(II) chains.

During studies on the amino acid sequence of bovine nasal cartilage collagen, the cyanogen bromide peptide alpha1(II)-CB11 was degraded to smaller peptides with trypsin. One of the tryptic peptides, T5, which contained 39 residues was shown by amino acid and sequence analyses to occur in a predominant form that contained glutamine at position 5 and in a second form with leucine at this site. In addition to the heterogeneity at this position, amino acid analyses of five different preparations revealed that the peptide with leucine contained a seryl residue not found in the major form. Sequence heterogeneity at a third position of alpha1(II) was demonstrated by the isolation of a hexapeptide (T2) from the trypsin digest of alpha1(II)-CB11 which contained 0.21 residue of alanine and 0.77 of leucine. Both the leucine and alanine of T2 were removed after the second cycle of subtractive Edman degradation. These data show that at least two types of alpha1(II) chains, designated as alpha1(II)Major and alpha1(II)Minor, exist in bovine nasal cartilage. Further considerations suggest that these two chains are probably not variants derived from allelic genes but are the products of separate genes.

Amino Acid Sequence↗
PubMed1977

Phosphoprotein from dentin. New approaches to achieve and assess purity.

Phosphorprotein extracted from rat incisors was purified by passage through a sulfonated polystyrene column. The phosphoprotein that emerged in the void volume contained 54% phosphoserine + serine and 36% aspartic acid and, in contrast to that obtained by DEAE-cellulose chromatography, was devoid of proline, valine, isoleucine, leucine, tyrosine, phenylalanine and arginine. Gel electrophoresis of the material purified on sulfonated polystyrene columns gave one major phosphate-containing band which would not stain with Coomassie Blue. EDTA or acetic acid demineralization yielded phosphoprotein preparations with identical compositions and electrophoretic properties. These data show that purification procedures reported earlier are insufficient.

Amino Acids↗
PubMed1977

Noncollagenous proteins of a rat dentin matrix possessing bone morphogenetic activity.

An insoluble preparation of rat dentin matrix was shown to possess bone morphogenetic protein (BMP) activity, i.e. the capacity to induce the formation of catilage and bone when implanted intramuscularly. Since BMP activity was previously attributed to noncollagenous proteins (NCP) of bone and dentin, the nature of NCP of the rat dentin was examined. After treatment of the matrix with purified bacterial collagenase, three NCP were solubilized concomitantly with digestion of the dentin collagen to smaller peptides. The three proteins were separated by anion-exchange chromatography on DEAE-cellulose. Two of the NCP were rich in asparate, glutamate, glycine, serine, and alanine, and thus displayed compositions similar to acidic proteins of other connective tissues. The third NCP was shown by amino acid composition to be the aspartate, serine-rich phosphoprotein, which occurs mostly in a soluble form in rat dentin. This observation supports the view that a portion of dentin phosphotprotein is firmly bound.

Amino Acids↗
PubMed1977

The phosphoprotein of rabbit in cisors.

The phosphoprotein of continually erupting rabbit incisors was extracted from decalcified teeth and purified by gel filtration and ion-exchange chromatography. Chemical characterization revealed that its composition was very similar to that of rat incisor and bovine molar phosphoproteins. The presence of similar acidic proteins in the dentin of various mammals is consistent with the suggestion that they are involved in the mineralization process.

Amino Acids↗
PubMed1976

The covalent structure of cartilage collagen. Amino acid sequence of the NH2-terminal helical portion of the alpha 1 (II) chain.

The amino acid sequence of 162 residues from the NH2-terminal region of bovine alpha 1 (II) is reported. Automated sequence analysis of chains from pepsin-treated type II collagen indicated the sequence and order of two CNBr peptides, alpha 1 (II)-CB2 and alpha 1 (II)-CB3, at the beginning of the repetitive triplet sequence of alpha 1 (II). The sequences of alpha 1 (II)-CB6, alpha 1 (II),-CB12, and 39 residues of alpha 1 (II)-CB11 were determined largely by automated Edman degradation. Comparative sequence data are reported which indicate that the level of homology between alpha 1 (I) and alpha 1 (II) chains in the NH2-terminal region is about 80%. A similar level of homology was reported for the central portions of these chains (Butler, W.T., Miller, E.J., Finch, J.E., Jr., and Inagami, T. (1974), Biochem. Biophys. Res. Commun. 57 190). The degree of intraspecies variability between chain types is thus greater than the interspecies variability for a single chain type. Within the sequence reported here, the alpha 1 (II) chain contains glucosylgalactosylhydroxylysine at three positions. The corresponding sequence of alpha 1 (I) contains only one clycosylated hydroxylysine with the other two positions occupied by lysyl residues.

Amines↗
PubMed1976

Purification and some properties of the phosphoprotein from rat incisors.

The phosphoprotein of rat incisors has been purified by successive gel and ion-exchange chromatography. The product gave a single band on polyacrylamide gel electrophoresis and contained approximately 34% phosphoserine and 32% aspartic acid. Alkaline elimination experiments showed all the phosphate to be present as phosphoserine. Ultraviolet spectra in the presence or absence of ATP showed that the phosphoprotein did not contain an nucleotide moiety as suggested by Veis, A., Spector, A. R. and Zamoscianyk, H. ((1972) Biochim. Biophys. Acta 257, 404-413) for bovine dentin phosphoprotein.

Amino Acids↗
PubMed1976

Cleavage of Type II and III collagens with mammalian collagenase: site of cleavage and primary structure at the NH2-terminal portion of the smaller fragment released from both collagens.

Collagenase cleavage of human Type II and III collagens has been studied using a highly purified preparation of rabbit tumor collagenase. Progress of the reactions in solution was followed by viscometry and the results indicated that under the conditions employed Type III collagen molecules were cleaved at approximately five times the rate of Type II molecules. Cleavage products of the reactions were isolated in denatured form by agarose molecular sieve chromatography. The molecular weights and amino acid compositions of the products demonstrated that Type II and III molecules had been cleaved at the characteristic three-quarter, one-quarter locus, giving rise to a large fragment derived from the NH2-terminal portion of the molecule and a smaller fragment representing the COOH-terminal region. The amino acid sequence at the NH2-terminal portion of the smaller fragment derived from Type II collagen was determined to be Ile-Ala-Gly-Gln-Arg, and the corresponding region from Type III collagen was found to have the sequence Leu-Ala Gly-Leu-Arg. These sequences for alpha1(II) and alpha1(III) chains adjacent to the site of collagenase cleavage along with previous data for alpha1(I) and alpha2 chains indicate that the minimum specific sequence required for collagenase cleavage is Gly-Ile-Ala or Gly-Leu-Ala. Inspection of the available sequence data for collagen alpha chains indicates that the latter sequences are found in at least three additional locations at which collagenase cleavage does not occur. Each of the sequences which are apparently not substrates for collagenase, however, are followed by a Gly-X-Hyp sequence. We suggest, then, that a minimum of five residues in collagen alpha chains COOH-terminal to the cleavage site comprise the substrate recognition site.

Amino Acid Sequence↗
PubMed1976

Specific in vitro binding of radiolabeled antibodies to cell surface antigens: interaction of antihuman thymocyte globulin with human target cells.

We have developed a highly sensitive and reproducible in vitro method to measure the rate and amount of binding of radiolabeled antibodies to target cells. We reduced non-specific binding of the antibodies to the target cells approx. 92% by removing protein aggregates from the antibody solutions. Using a specially designed cup that simultaneously allows washing and collection of target cells, cell loss was eliminated. This method was used to study the in vitro binding properties of the IgG fraction of anti-human thymocyte globulin (ATG) to nucleated human cells and to cells of other species. We found the initial rapid uptake of labeled ATG-IgG slowed with prolonged incubation. Incubation temperature and ATG concentration increased the rate of uptake. Sequential absorption studies indicated that initial uptake was due to rapidly binding antibodies. After these antibodies were removed, the rate of binding for antibodies that remained was several fold less than that of the antibodies removed by the initial absorption. Since temperature and the concentration of antibody and target cells can be rigidly controlled, this in vitro model system is ideally suited to quantify optimal conditions and kinetics of antibody binding to cell membrane antigens. Furthermore, the binding properties of antibody subpopulations in an antiserum may be determined by this technique. The maximum antibody binding capacity of various cell types can also be measured using the technique with a precision of +/- 14% on replicate determinations.

Animals↗
PubMed1976

The carbohydrate composition of experimental salivary pellicles.

The carbohydrate compositions of pellicles formed in vivo and others formed in vitro from submandibular, parotid, and mixed (submandibular-parotid) saliva were determined using gas-liquid chromatography. Samples of the total pellicles as well as the relatively acid-soluble supernates and acid-insoluble sediments were collected, analyzed, and compared. The differences in carbohydrates composition between the supernates and sediments, particularly in the in vivo and in vitro mixed salivary pellicles, suggest that the total pellicle is composed of more than one component. In each instance obvious differences in composition between th pellicle and the saliva from which it was formed indicated that pellicle formation is a highly selective process. Glucose:galactose ratios of approximately 1:1 were found in each of the total pellicles. These data suggest that at least one pellicle component is an unusual glycoprotein in that it contains high levels of glucose. The total submandibular salivary pellicle and both its fractions were remarkably similar in carbohydrate composition to the counterparts formed from parotid saliva alone. The data strongly suggest that there are present in both submandibular and parotid saliva similar glycoproteins that are selectively deposited onto etched enamel as the initial pellicle.

Amino Sugars↗
PubMed1975

Proteins of the periodontium. Identification of collagens with the [alpha1(I)]2alpha2 and [alpha1(III)]3 structures in bovine periodontal ligament.

Insoluble collagen was prepared from bovine periodontal ligament. Isolation and characterization of CNBr peptides originating from the alpha1(I), alpha2, and alpha1(III) chains showed that the tissue contained both type I and type III collagens. Further evidence for the presence of type III collagen was obtained by the isolation of alpha1(III) chains from pepsin-treated ligament collagen, with properties similar to those of human alpha1(III) chains. Estimates based on the amounts of certain CNBr peptides indicated that about one-fifth of the collagen of periodontal ligament is type III, the remainder being type I collagen.

Amino Acids↗
PubMed1975

Mineralization of dentin, bone and tendon in vitro.

Bovin dentin, bone and tendon slices, and rat bone, readily mineralize to variable degrees after demineralization by (EDTA) at pH 7.4, but they fail to mineralize after dimeralzation with acetic acid (HAc) at pH3.0. The demineralized dentin, but neither bone nor tendon, contained organically bound phosphate. The EDTA-demineralized dentin contained less phosphate than HAc-demineralized dentin. HAc-demineralized rat dentin contained high levels of phosphate. Since the EDTA- and HAc-demineralized rat dentin contained widely different levels of phosphate, yet both mineralized, it was concluded that phosphoprotein had little effect on nucleation. The reason why HAc-demineralized tissue other than rat dentin failed to nucleate and mineralize was not clarified.

Acetates↗