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Biomedical subjects

M J Glimcher

Publications and source records attributed to M J Glimcher.

At least 19 recordsLinked to original sources
PubMed1979

Identification of O-phosphoserine, O-phosphothreonine and gamma-carboxyglutamic acid in the non-collagenous proteins of bovine cementum; comparison with dentin, enamel and bone.

O-phosphoserine [Ser(P)], O-phosphothreonine [Thr(P)], and gamma-carboxyglutamic acid (Gla) have been identified in native, calcified cementum and in non-collagenous proteins which can be extracted from the tissue in EDTA at neutral pH. The concentrations of Ser(P) and Thr(P) and the amino acid composition of the EDTA extractable proteins are more similar to those found in bone than in dentin or enamel. The concentration of Gla in cementum is lower than it is in bone and higher than it is in enamel, which contains essentially no Gla. Based on the contents of Gla in these mineralized tissues and the distribution of alkaline and acid phosphatases in these tissues, it is speculated that Gla may be part of these or other proenzymes rather than being involved directly and structurally with the deposition of the mineral phase.

1-Carboxyglutamic Acid↗
PubMed1979

Phosphopeptides and gamma-carboxyglutamic acid-containing peptides in calcified turkey tendon: their absence in uncalcified tendon.

Uncalcified samples of turkey tendon obtained prior to calcification, and other samples from areas of tendon that never calcify, contain little or no O-phosphoserine [Ser(P)], O-phosphothreonine [Thr(P)] and gamma-carboxyglutamic acid (Gla). Significant amounts of all three of these Ca2+-binding amino acids, which are found in EDTA-extractable, non-collagenous proteins, are detected coincident with the onset of mineralization of a tendon and increase in concentration as mineralization proceeds.

1-Carboxyglutamic Acid↗
PubMed1979

Identification of phosphopeptides and gamma-carboxyglutamic acid-containing peptides in epiphyseal growth plate cartilage.

Uncalcified cartilage from the epiphyseal portion of bovine scapulae, both distant and adjacent to the epiphyseal growth plate, and the calcified cartilage of the epiphyseal growth plate itself were analyzed for the presence of O-phosphoserine [Ser(P)], O-phosphothreonine [Thr(P)] and gamma-carboxyglutamic acid (G1a). Only trace amounts of these Ca2+-binding amino acids or the peptides containing them were found in the unmineralized tissues. In contrast, whole calcified cartilage, and especially the most mineralized fraction obtained by density centrifugation, contained considerable amounts of all three amino acids. Essentially all of the G1a and the majority of the Ser(P) and Thr(P) were present in non-collagenous, non-diffusible proteins extractable in EDTA at near-neutral pH.

1-Carboxyglutamic Acid↗
PubMed1979

Identification of organic phosphorus covalently bound to collagen and non-collagenous proteins of chicken-bone matrix. The presence of O-phosphoserine and O-phosphothreonine in non-collagenous proteins, and their absence from phosporylated collagen.

Non-collagenous phosphoproteins, almost all of which can be extracted in EDTA at neutral pH in the presence of proteinase inhibitors, are identified in the matrix of chicken bone, and are therefore not covalently bound to collagen. Similarly, all the peptides containing gamma-carboxyglutamic acid are present in the EDTA extract and none in the insoluble residue, confirming that none is covalently linked to chicken bone collagen. However, organic phosphorus is also found to be present in chicken bone collagen, principally in the alpha2-chains. Of the total protein-bound organic phosphorus present in chicken bone matrix, approx. 80% is associated with the non-collagenous proteins and 20% with collagen. The soluble non-collagenous proteins contain both O-phosphoserine and O-phosphothreonine and these account for essentially of their organic phosphorus content. In contrast, collagen contains neither O-phosphoserine nor O-phosphothreonine. Indeed, no phosphorylated hydroxy amino acid, phosphoamidated amino acid or phosphorylated sugar could be identified in purified components of collagen, which contain approximately four to five atoms of organic phosphorus per molecule of collagen. Peptides containing organic phosphorus were isolated from partial acid hydrolysates and enzymic digests of purified collagen components, which contain an as-yet-unidentified cationic amino acid. These data, the very high concentrations of glutamic acid in the phosphorylated peptides, and the pH-stability of the organic phosphorus moiety in intact collagen chains strongly suggest that at least part of the organic phosphorus in collagen is present as phosphorylated glutamic acid. This would indicate that the two major chemically different protein fractions in chicken bone matrix that contain organic phosphorus may represent two distinct metabolic pools of organic phosphorus under separate biological control.

1-Carboxyglutamic Acid↗
PubMed1979

Identification of gamma-glutamyl phosphate in the alpha 2 chains of chicken bone collagen.

Purified components of chicken bone collagen contain approximately 4 atoms of organic phosphorus per mol of collagen, located principally in the alpha 2 chains. Previous analyses have demonstrated the absence of O-phosphoserine, O-phosphothreonine, and other phosphorylated hydroxy amino acids, phosphoamidated amino acids, and phosphorylated sugars. In the present report we establish that chicken bone collagen contains gamma-glutamyl phosphate. This was accomplished by the isolation of tritiated alpha-amino-delta-hydroxyvaleric acid after reductive cleavage with NaB[3H]H4 of the gamma components, the alpha 2 chains, and peptides enriched in organic phosphorus that were derived from the alpha 2 chains. Tritiated alpha-amino-delta-hydroxyvaleric acid was not detected in any of the following unphosphorylated proteins after cleavage with NaB[3H]H4:albumin and lysozyme, the alpha 2 chains of several unmineralized tissues, and, most importantly, dephosphorylated alpha 2 chains of chicken bone collagen. The alpha 2 chain of chicken bone collagen is the first structural protein found to contain an acyl phosphate.

Animals↗
PubMed1979

Phosphopeptides of enamel matrix.

Although the tripeptides Glu-O-Phosphoserine-Tyr and Glu-O-Phosphoserine-Leu have been identified in embryonic bovine enamel proteins, 1, 2 the issue of whether both sequences occur in each of the phosphopeptides, or whether certain sequences occur in specific peptides only, has recently been resolved by isolating homogeneous samples of E33 and E44. All three of the Ser residues of both peptides are phosphorylated. All three in E3 are in the sequence Glu-O-Phosphoserine-Leu, and all three in E4 are in the sequence Glu-O-Phosphoserine-Tyr. It was not possible to sequence either of the polypeptide chains directly by automatic peptide sequencing. However, a partial sequence of E4 was constructed from data derived from peptides isolated after cyanogen bromide, trypsin and chymotrypsin digestions. The presence of Glu, Tyr and Leu adjacent to and near the O-Phosphoserine [Ser(L)] residues and the 2 degrees, 3 degrees and higher ordered structures of the enamel phosphopeptides may be important in calcium binding and mineralization.

Amino Acid Sequence↗
PubMed1979

Gross and histological abnormalities of the talus in congenital club foot.

Gross and histological abnormalities were demonstrated in a club-foot talus from a boy with multiple congenital anomalies who died when he was nine days old. Both tali were studied, the one from the club foot and the one from the normal foot. The gross anomalies involved the smaller size of the club-foot talus and the increased medial deviation of a stunted, misshapen head and neck region. Serial histological sections of both tali allowed for a three-dimensional geometric appreciation of both bones and an assessment of the nature and extent of histological and cytological features. The ossification center of the club-foot talus was absolutely and relatively smaller than that of the normal talus. It was eccentrically positioned, being more lateral and anterior than that of the normal talus. The marked histological abnormalities seen in the head and neck region of the club-foot talus involved extensive breaching of the endochondral sequence by vessels. The posterior aspect of the endochondral sequence and ossification center was normal. The extra-osseous and intra-osseous blood supply of the two tali was normal with the exception of the increased and irregular breaching of the endochondral sequence in the club-foot talus. This study demonstrates histological abnormalities in the head and neck region of the club-foot talus, which was most abnormal grossly. The eccentric position of the secondary ossification center as well as its related vascular abnormalities do not support a theory of developmental arrest of the talus but appear sufficiently abnormal to support the theory of a primary defect in the cartilage anlage. Clinically, one must bear in mind that early open reduction of the talocalcaneal navicular joint in a foot such as this would have served to reposition the navicular onto a talus that still was structurally abnormal.

Clubfoot↗