Hs. Kim et al., INTRANEPHRON DISTRIBUTION OF CYSTEINE S-CONJUGATE BETA-LYASE ACTIVITYAND ITS IMPLICATION FOR HEXACHLORO-1,3-BUTADIENE-INDUCED NEPHROTOXICITY IN RATS, Archives of toxicology, 71(3), 1997, pp. 131-141
The intranephron distribution of two major cysteine S-conjugate beta-l
yases was determined in order to clarify the role of these enzymes in
promoting the nephrotoxicity associated with certain halogenated xenob
iotics. Various nephron segments [i.e., glomerulus, early, middle, and
terminal portions of the proximal tubule (S-1, S-2, and S-3 respectiv
ely), the thick ascending limb, the distal tubule, and the collecting
tubule] were isolated by microdissection from collagenase-treated rat
kidneys. Each segment was dissected in Hanks' solution, solubilized wi
th Triton X-100, and applied to a micropolyacrylamide gel constructed
with a continuous gradient. The gels were subjected to electrophoresis
and then incubated in the dark in a solution containing S(1,2 dichlor
ovinyl)-L-cysteine (DCVC), sodium alpha-keto-gamma-methiolbutyrate, ph
enazine methosulfate, and nitroblue tetrazolium. The position of cyste
ine S-conjugate beta-lyase- and L-amino acid oxidase activities in the
gels was revealed by the presence of blue formazen dye bands. The rel
ative intensities of the bands were determined by optical scanning wit
h a microdensitometer. Three bands were detected: band I (M(r) similar
to 330 000) corresponds to a recently described high M, cysteine S-co
njugate beta-lyase whereas band III (M(r) similar to 90 000) correspon
ds to a lower M(r) cysteine S-conjugate beta-lyase (identical to cytos
olic glutamine transaminase K). Band II (M(r) similar to 240000) corre
sponds to L-amino acid oxidase (a unique activity of the B isoform of
rat kidney L-hydroxy acid oxidase).