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Synthesis and turnover of membrane glycoconjugates in monolayer culture of pig and human epidermal cells
Author(s) -
DAVIES HELEN W.,
TROTTER M.D.
Publication year - 1981
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.1981.tb00751.x
Subject(s) - glycoconjugate , sialic acid , glycoprotein , biochemistry , trypsin , membrane glycoproteins , biology , glucosamine , epidermal growth factor , cell , membrane , cell culture , chemistry , microbiology and biotechnology , enzyme , receptor , genetics
SUMMARY The regeneration and turnover of the surface glycoconjugates of trypsin‐prepared pig and human cultured epidermal cells have been determined using the glycoprotein precursors N‐acetyl‐D‐(I‐ 3 H) glucosamine ( 3 H‐NAG) and N‐( 3 H)‐acetyl‐D‐mannosamine ( 3 H‐NAM). Sialic acid assays have been performed on similar unlabelled cells. The major points which emerged from this study were:1 Trypsin‐damaged cell surfaces are rapidly repaired, probably by normal membrane turnover. There was a 12% regeneration of sialic acid within 2 h and total resynthesis occurred within 24 h. 2 The presence of an internal membrane system, part of which also demonstrates turnover, probably contributes to the speed of surface membrane repair. Some of the glycoprotein/sialic acid of this internal membrane system (30%) remains bound for a considerable length of time. 3 The membrane turnover maintains the cell in equilibrium so that total loss equals the synthesis of glycoprotein. 4 The equilibration of 3 H‐NAG or 3 H‐NAM uptake between 24 and 48 h is limited by the relative concentrations of glucose and labelled sugar in the medium at this time. 5 3 H‐NAM was a more specific marker of glycoprotein than 3 H‐NAG. 6 The results for human epidermal cells closely matched those for pig epidermal cells, indicating that pig cells can be used as a model for human cells.