Maturation Analysis in Connective Tissue Proteins by [14C]Cyanide Incorporation

The presence of desmosine and isodesmosine in eggshell membrane protein

Investigation of eggshell membrane by amino acid analysis and radioimmunoassay established the presence of the crosslinking amino acids desmosine and isodesmosine at levels of 28 microgram/100 mg dry weight. Specific enzymatic and chemical hydrolysis indicates that these crosslinks are present as constituents of eggshell membrane protein and do not reflect the presence of small amounts of elastin. The eggshell membrane protein has approximately 10 times the level of lysine-derived aldehyde found in elastin.

Crosslinking profiles of elastin from anatomically defined regions of the lung

Elastin was isolated and purified by a procedure which sequentially removed lipids, collagen, structural glycoproteins and the microfibrillar proteins. Crosslinking profiles were obtained by column chromatography either after reduction with 3[H]NaBH4 or after reaction with 14[C]NaCN and NH3. Examination of the crosslinking profiles of the elastins from various tissue regions revealed differences in the type, distribution and quality of crosslinks.

Isolation, purification, and cross-linking profiles of elastin from lung and aorta

Elastin from anatomically defined regions of young calf lung and dog aorta was isolated and purified by a procedure which sequentially removed lipids, collagen, structural glycoproteins, and the microfibrillar proteins without apparent damage to the cross-linking residues, which have been shown to be sensitive to autoclaving and hot alkali treatment. One of the methods described was effective in obtaining pure elastin from lung parenchyma. Visceral pleura was found to be the richest source (25% dry weight) of elastin in the lung tissues examined. The amino acid compositions of the elastins purified by different methods were compared for purity and for the detection of possible damage to cross-linking compounds. Cross-linking profiles were obtained by column chromatography either after reduction with 3[H]NaBH4 or after reaction with 14[C]NaCN and NH3. The 3[H]NaBH4 method, under carefully controlled conditions, proved not to be quantitatively reproducible. The reaction of elastin with 14[C]NaCN and NH3 appeared preferable due to its reproducibility; this procedure required one type of hydrolysis for the analysis of all the cross-linking compounds. Examination of the cross-linking profiles of the elastins from various tissue regions revealed differences in the type, distribution, and quality of cross-links.