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J G Leslie

Publications and source records attributed to J G Leslie.

14 recordsLinked to original sources
PubMed1986

Quantitation of elastin through measurement of its pentapeptide content.

Digestion of insoluble porcine elastin with thermolysin produces a number of discrete small peptides. That present in highest concentration is the pentapeptide valyl-glycyl-valyl-prolyl-glycine (VGVPG) derived from the portion of the polymer containing extensive repeats of this sequence. Among eukaryotes, this sequence appears to be found only in elastin and its precursor tropoelastin. In the pig this is represented by peptide W4 of a tropoelastin tryptic digest (Sandberg, L.B., et al. Path. Biol. 33, 266-274, 1985). Quantitation of this peptide by HPLC separation, monitoring its absorption at 212 nm, offers a simple reliable means of measuring purified insoluble elastin as well as non-purified elastin in fat-free tissue samples. Digestion times and incubation temperatures are discussed. The method is sensitive enough to accurately quantitate elastin at the 2 to 3 microgram level.

Amino Acid Sequence↗
PubMed1985

Elastin covalent structure as determined by solid phase amino acid sequencing.

The amino acid sequences of 16 large tryptic fragments of aortic tropoelastin have been determined establishing the presence of several repeating structures: GVP, GGVP, PGVGV, PGVGVA, and AGVPGFGVG. The methodologies for achieving these results by solid phase sequencing are reviewed and also the possible biologic significance of the unusual primary structures of elastin are discussed.

Amino Acid Sequence↗
PubMed1981

In vitro studies of elastin metabolism.

Neonatal pig and rat aortas were studied for their ability to synthesize elastin in an in vitro situation. Smooth muscle cells from the rat aorta produced excellent multilayered cultures and produced soluble elastin (tropoelastin), insoluble elastin, and small amounts of collagen. BAPN proved to be toxic to these cells, adversely affecting the level of extracellular protein production. Tissue minces from pig aorta continued to synthesize elastin for two hours after removal. However, a 24 hour study indicated that elastin synthesis had almost completely shut down and that collagen synthesis continued in an apparently normal fashion. It is concluded that in vitro elastin synthesis is an extremely sensitive process easily altered by culture conditions and the addition of extraneous substances such as BAPN, and also highly influenced by the past history of the smooth muscle cells involved.

Animals↗
PubMed1979

Intermolecular cross-links in collagen of human placenta.

1. There are four reducible cross-links in human placenta collagen. The principal one is dehydrodihydroxylysinorleucine. the next in abundance is dehydrohydroxylysinorleucine. The minor components are dehydrolysinonorleucine and dehydrohistidinohydroxymerodesmosine. 2. With increasing length of gestation, the collagen incorporates more tritium radioactivity into its reducible cross-links, with its maximum incorporation at the second trimester. The uptake declines thereafter. 3. Alkaline hydrolysis reveals that both dehydrodihydroxylysinonorleucine and dehydrohydroxylysinonorleucine occur in vivo partly as glycosylated complexes.

Chemical Phenomena↗
PubMed1977

Polymorphism in human uterine collagen.

Fifty percent of human uterine collagen has been solubilized by limited pepsin digestion. Carboxymethyl cellulose-, Bio-gel A-5m-chromatography and amino acid analysis revealed that the solubilized collagen consists of 20% Type III and 80% Type I collagen. Reduction and alkylation reactions indicated that the alpha1(III) collagen is in the tissue as a trimer with the chain composition [alpha1(III)].

Adult↗
PubMed1976

The intermolecular cross-links in uterine collagens of guinea pig, pig, cow, and human beings.

The intermolecular cross-links have been studied in the uterine insoluble collagen of guinea pig, pig, cow, and human beings with a single given procedure. After NaB3H4 reduction, there are three intermolecular cross-links; namely, dihydroxylysinonorleucine, hydroxylysinonorleucine, and histidinohydroxymerodesmosine. In human uterine collagen samples these reduced cross-links are present in equal amounts. The reduced intermolecular collagen cross-links of uterine leiomyoma are very similar to those of the normal uterine tissue. Dihydroxylysinonorleucine is the principal reduced cross-link in uterine collagen of guinea pig, pig, and cow. Alkaline hydrolysis reveals that dehydrodihydroxylysinonorleucine and dehydrohydroxylysinonorleucine occur in vivo as glycosylated derivatives.

Adult↗