Limited proteolysis of high molecular weight histidine-rich protein of rat epidermis by epidermal proteinases.
Epidermal proteinases, which may be involved in proteolysis of Mr greater than 300k histidine-rich protein in epidermis, were studied by SDS-PAGE analysis. Mr greater than 300k histidine-rich protein was extracted from granular cells of 2-day-old rats in citric acid-sucrose solution and separated from proteinases and smaller Mr proteins by Sephacryl S-300 column chromatography. The proteinase-free histidine-rich protein was stable in pH 3.5-9 at 37 degrees C for 12 h. Proteinases were partially purified from rat epidermis and inhibitor spectrum determined for each enzyme. Limited hydrolysis of Mr greater than 300k histidine-rich protein yielded a derivative of Mr 56k with cathepsin D at pH 3.5-7.5 and a serine proteinase at pH 7-9. Further proteolysis of Mr 56k protein to Mr 44k and a doublet of Mr 45k and 47k also was detected with cathepsin D at pH 3.5 and 7.5, respectively, while the serine proteinase degraded Mr 56k protein to a number of protein bands. Cathepsins B and L degraded Mr greater than 300k protein but no specific predominant product was identified. We suggest that cathepsin D and the serine proteinase may play a role in in situ processing of histidine-rich protein during cornification.
Kashima
M
M
Department of Dermatology, University of California, San Francisco 94143-0536.
Fukuyama
K
K
Kikuchi
M
M
Epstein
W L
WL
D000818:Animals; D002402:Cathepsin D / Q000302:isolation & purification / Q000378:metabolism; D004817:Epidermis / Q000201:enzymology / Q000378:metabolism*; D006868:Hydrolysis; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism; D000099053:Histidine-Rich Glycoprotein
D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; D010447:Peptide Hydrolases; D012697:Serine Endopeptidases; D002402:Cathepsin D