In vitro aminoacylation assay Seryl-or leucyl-tRNA synthetases were partially purified from C.zeylan-the proteins. Since the C.cylindracea strain was developed oides cells as described previously , both of the industrially for the production of lipase, such multifunc- Large-scale purification of tRNA Ser CAGs from C.zeylanoides and C.cylindracea mmol) and leucine (11.5 MBq/mmol) were from Amersham. 5-fluoroorotic acid monohydrate (5FOA) was from PCR inc. 3Ј-Biotinylated Candida cylindracea cells (3.1 kg) were treated with phenol, from which 150 000 A 260 units of unfractionated tRNA were extracted. Eighty DNA probes were synthesized by Sci. Media, Japan. Synthetic RNA oligomers and a chimeric oligonucleotide composed of DNA and 2Ј-O-thousand A 260 units of tRNA mixture were obtained by DEAE-cellulose chromatography with stepwise elution, which was then applied onto a methyl RNA were synthesized by Genset Co. Ltd. Most of the enzymes used for the microsurgery were from Takara Shuzo (Tokyo, Japan).