Properties and nature of a cysteine proteinase inhibitor located in keratohyalin granules of rat epidermis.
The pI 4.7, 14.5 kDa hematoxylin-stainable protein (HSP) from rat epidermis inhibited the activities of the cysteine proteinases papain, ficin, cathepsins B, H and L with similar inhibitory characteristics as recombinant cystatin-alpha. Proteinases of other classes were not inhibited. The inhibitory activity of HSP was heat stable in the wide pH range of 3.0-10.0. Polyclonal antibodies against HSP cross-reacted with cystatin-alpha and the molecular mass of HSP was similar to that of cystatin-alpha, though its isoelectric point was different. The in vivo location of both HSP and cystatin-alpha is on keratohyalin granules in epidermis as detected by indirect immunofluorescence technique using individual antibodies. Therefore it is highly probable that HSP is a cystatin-alpha derivative or a very similar proteinase inhibitor belonging to a family of cystatins.
Department of Dermatology, Kinki University School of Medicine, Osaka, Japan.
M
M
Takahashi
T
T
Tezuka
T
T
Towatari
N
N
Katunuma
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D002401:Cathepsin B / Q000037:antagonists & inhibitors; D056655:Cathepsin H; D056668:Cathepsin L; D002403:Cathepsins / Q000037:antagonists & inhibitors; D015891:Cystatins / Q000032:analysis; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D010450:Endopeptidases; D005361:Ficain / Q000037:antagonists & inhibitors; D005455:Fluorescent Antibody Technique; D015603:Keratinocytes / Q000032:analysis*; D010206:Papain / Q000037:antagonists & inhibitors; D051381:Rats; D012867:Skin / Q000032:analysis*
D000596:Amino Acids; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; D056668:Cathepsin L; C534280:Ctsl protein, rat; D056655:Cathepsin H; C534128:Ctsh protein, rat; D010206:Papain; D005361:Ficain