Author/Editor		Rozhin, J; Robinson, D; Stevens, MA; Lah, TT; Honn, KV; Ryan, RE; Sloane, BF
Title		Properties of a plasma membrane-associated cathepsin B-like cysteine proteinase in metastatic B16 melanoma variants
Type		članek
Source		Can Res, Suppl
Vol. and No.		Letnik 47
Publication year		1987
Volume		str. 6620-8
Language		eng
Abstract		Activities of a cathepsin B-like cysteine proteinase have previously been observed to correlate with the malignancy of several animal andhuman tumors. Plasma membrane fractions of some of these tumors have been found to be enriched in cathepsin B-like activity. We have determined the subcellular distribution of this enzyme and three additionallyusosomal hydrolases (cathepsin H, a-hexosaminidase, and beta-glucuronidase) in normal murine liver and six metastatic variants of the B16 melunoma. The tissues w'ere fractionated initially by differential centrifugation followed by Percoll density gradient centrifugation of the light mitochondrial fraction. Two fractions were obtained: an L-2 fraction enriched in all four lysosomal hydrolases; and an L-1 fraction enriched in a marker enzyme for the plasma membrane. Cathepsin B-like and beta-hexosaminidase activities, but not the other hydrolase activities, w'ere also found to be enriched in the L-1 fractions of the metastatic B16 tumors. W'e explored the nature of the association of the cathepsin B-like activity with the plasma membrane using fractions from the spontaneouslv metastatic B16 amelanotic melanoma. Activity could not be dissoriated from the plasma membrane fraction by washing w'ith a physiological salt solution suggesting that it wuas not adsorbed to this fraction nonspecificallv, nor could it be displaced by marnose 6-phosphate or other sugars which compete for binding to the known lysosomal receptors. Abstract truncated at 2000 characters.
Descriptors		CATHEPSIN B MELANOMA