Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003969 (vitamin C deficiency)
 625 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Significant amount of 45-kDa polypeptide was found to be present in the cultured medium of chick aortic smooth muscle cells. The polypeptide as well as tropoelastin (65-kDa) reacted with monoclonal antibody for tropoelastin. Pulse-chase experiments revealed that the relative density of the 45-kDa polypeptide to tropoelastin increased with chase periods. Partially purified radioactive tropoelastin (65-kDa) was converted to a 45-kDa polypeptide fragment in the test tube. The processing from the 65- to the 45-kDa polypeptide in the test tube was inhibited by ethylenediaminetetraacetic acid but not by N-ethylmaleimide and aminophenylmethylsulfonyl fluoride. These results indicate that the 45-kDa fragment is a degradation product of tropoelastin and that processing is mediated by enzymatic cleavages with metal proteinase. Fully hydroxylated tropoelastin treated with ascorbic acid was more resistant to the enzymes than underhydroxylated tropoelastin with scorbutic condition, suggesting that the structural stability of tropoelastin is also involved in the processing rate.
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PMID:Presence of elastin-related 45-kDa fragment in culture medium: specific cleavage product of tropoelastin in vascular smooth muscle cell culture. 759 51

Treatment of cultured smooth muscle cells with ascorbic acid resulted in an accumulation of tropoelastin in the culture medium in dose-dependent and exposure time-dependent manner under the condition in which collagen synthesis was stimulated 2-fold. The steady-state level of elastin mRNA was essentially unchanged, whereas collagen mRNA content increased 2-fold by ascorbic acid treatment. Newly synthesized tropoelastin was hydroxylated in the presence of ascorbic acid but was underhydroxylated in a scorbutic condition. Short pulse experiments showed that the secretion rate of tropoelastin was unaltered by ascorbic acid treatment. Pulse-chase experiment demonstrated that the level of fully hydroxylated tropoelastin in the medium of ascorbate-treated cells was greater than that of under-hydroxylated tropoelastin. These results indicate that accumulation of tropoelastin in the medium by ascorbic acid is related to an increased stability of hydroxylated tropoelastin and/or its impaired incorporation into insoluble elastin.
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PMID:Accumulation of tropoelastin by a short-term ascorbic acid treatment in the culture medium of aortic smooth muscle cells in vitro. 858 26