
CathepsinSisalysosomalcysteineproteaseofthepapainfamily.HumanCathepsinSissynthesizedasapreproenzymeof331aminoacidresiduesconsistingasignalpeptide(residues1-16),aproregion(residues17-114),andthematureenzyme(residues115-331).
Image:CathepsinSstainingofimmersionfixedparaffin-embeddedsectionsofhumanlymphnode(15µg/mLovernightat4°C).TissuewasstainedusingtheAnti-GoatHRP-DAB(brown)andcounterstainedwithhematoxylin(blue).
CathepsinS isexpressedinhumanadiposetissueandcertaintumors.IthasalsobeenshowntobeabletofunctionasanelastaseoverabroadpHrangeinalveolarmacrophages.Transcriptvariantsutilizingalternativepolyadenylationsignalsexistforthisgene.