Amino Acid Composition Of Elastin Research Articles

Elastin in the human intervertebral disk

The elastic fiber and elastin in the human yellow ligament and intervertebral disk were studied histologically and biochemically. The elastic fiber in the human intervertebral disk, which until now had not been clearly identified microscopically, was observed clearly. We found the distribution of the elastic fiber in the intervertebral disk to be very sparse and irregular, and its diameter was small, being about one-tenth of that found in the yellow ligament. The elastin contents of the yellow ligament and intervertebral disk were 46.7% +/- 0.9% and 1.7% +/- 0.2% respectively (mean +/- SE) of the total dry weight. The amino acid composition of elastin in the yellow ligament is similar to that of other tissue, as reported in the literature; however, that found in the intervertebral disk is significantly different. It would appear, therefore, that the elastin in the intervertebral disk is of a different type from that found elsewhere.

Purification and comparison of elastins from different animal species

A nondegradation method was developed for the isolation of elastin from tissues of 10 different animal species. Marked differences, involving primarily the neutral and aromatic amino acids, occurred in the amino acid composition of elastin of different species. The amino acid composition of elastins from a given species was constant for all the tissues studied.

Amino Acid Composition of Elastin in the Developing Chick Aorta

The presence of a non-collagenous, polar, alkali-soluble protein in intimate association with elastic fibres has been demonstrated by many workers. There have also been reports of apparently extraneous proteins associated with purified elastin, especially from foetal and very young tissues, even after conventional hot alkali treatment. In the present report the amino acid compositions of aortic elastins from foetal and young chicks of various ages indicate that hot alkali-purified elastin is associated with a considerable amount of a more polar protein, the quantity of this second component decreasing with increasing foetal age. The composition of this alkali-resistant component is very similar to that of the protein which is removed by hot alkali extraction. The persistence of this polar, alkali- resistant component suggests that it is not a simple impurity in the elastin, but rather may be an integral part of the newly synthesized foetal elastin molecule.

The amino acid composition of elastin in its soluble and insoluble state

The amino acid composition of elastin in its soluble and insoluble state

Amino acid composition of elastin in the developing human aorta

Elastin was prepared by alkali extraction of defatted human thoracic aortas from 14-, 23-, and 33-week-old fetuses and individuals aged 5 months and 1, 5, 10 and 51 years. The content of lysine decreased and that of desmosines and lysinonorleucine increased most markedly in fetal elastin. Several unknown ninhydrin-positive substances emerged in the basic region of the chromatogram. Two of these unknowns, eluted just after lysine, were incompletely resolved from each other and together comprised 9.6 residues per 1000 total residues in 14-week fetal elastin, decreasing to 8.3 at 23 weeks, to 2.5 residues at 33 weeks, and thereafter were present only in traces. Tyrosine increased in fetal elastin from 7.2 residues at 14 weeks to 11 at 23 weeks and to the adult level of 19 at 33 weeks. Certain other polar amino acids appeared to decrease in elastin with age. Individual variation in the amino acid composition of elastin appears to reside mainly in the relative proportions of glycine, alanine, and proline which make up exactly two-thirds of the total residues.