MOLECULAR PHARMACOLOGY, 43:660-665 ACCELERA TED COMMUNICATION Isolation and Expression of a cDNA Coding for Rat Kidney GyQaQIie Cyin#{128}.Conjugate fl-Lya -

The role of rat kidney cysteine conjugate $-Iyase in the produc-tion of nephrotoic thiols from S-cysteine conjugates of xenobi-otics has been well established. However, the factors controlling the cellular distribution and substrate specificity of the enzyme have yet to be elucidated. As an approach to this we have isolated a cONA for cysteine conjugate i3-lyase from a rat kidney cDNA library, using a combination of immunological and hybrid-ization screening. A full length cDNA was sequenced and its identity was confirmed by deduced molecular weight, deduced amino acid composition, the presence of a consensus pyridoxal phosphate (PLP) binding site in the deduced amino acid se-quence, kidney-specific expression of the corresponding mRNA, and the expression of (3-lyase and glutamine transaminase K activities in tissue culture cells transfected with the cDNA. The cDNA coxied for a protein of 48 kDa containing the sequenc