Gene, 171 (1996) 303-304 0 1996 Elsevier Science B.V. All rights reserved. 037%1119/96/$15.00 303 zyxwvutsr GENE 09777 Sequences of the lizard cDNAs encoding lactate dehydrogenase (LDH) isozymes A (muscle) and B (heart) * (Protein; gene; phylogenetic tree; reptile) Hideyuki Manner?, Stephen C.-M. Tsoi”, Daniel B. Pickfordb, John A. Donaldby**, Louis J. Guillette,b and Steven S.-L. Li” zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA “ Laboratory of Genetics, NIEHS, NIH, Research Triangle Park, NC 27709, USA. Tel. (l-919) 541-4253; and bDepartment of Zoology, University of Florida, Gainesville, FL 32611, USA. Tel (l-904) 392- 1098 Received by A. Nakazawa: 17 June 1995; Revised/Accepted: 18 September,‘21 September 1995; Received at publishers: 22 February 1996 SUMMARY The nucleotide and deduced amino acid sequences of cDNAs encoding L-lactate dehydrogenase (LDH) isozymes A (muscle) and B (heart) from the lizard, zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Sceloporus undulatus, were determined. The evolutionary relationships among LDH isozymes from animals, plants and bacteria are presented. L-lactate dehydrogenase (LDH, EC 1.1.1.27) is widely distributed among animals, plants and bacteria. In verte- brates, the LDH-A isozyme is best suited for pyruvate reduction in anaerobic tissues (muscle), whereas the LDH-B isozyme is superior for L-lactate oxidation in aer- obic tissues (heart). The electrophoretic patterns (not pre- sented) of LDH isozymes revealed that all five tetrameric isozymes formed by random combination of LDH-A and LDH-B subunits were present in the Florida scrub lizard, Sceloporus woodi, whereas only four tetrameric isozymes were observed in geckonid and skinkid lizards. The heterotetrameric A3Bl isozyme was absent in the gecko, and the heterotetrameric AlB3 isozyme was absent in the skink. Four-isozymes were previously reported in the Correspondence to: Dr. S.S.-L. Li at his present address: Institute of Life Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan 80824, ROC. Tel. (886-7) 532-1210; Fax (886-7) 532-1213; e-mail: LISSL@nsysu.edu.tw * On request, the authors will supply detailed experimental evidence for the conclusions reached in this Brief Note. ** Present address: Department of Biology, Deakin University, Geelong, Victoria 3217, Australia. Tel. (61-52) 27-2097. Abbreviations: aa, amino acids(s); bp, base pair(s); kb, kilobase or 1000 bp; LDH, L-lactate dehydrogenase; LDH, gene (DNA) encoding LDH; nt, nucleotide(s); UTR, untranslated region(s). PII SO378- I 119(96)00180- l snakes, Dryadophis melanolomus (Markert, 1968) and Crotalus viridis (Murphy and Crabtree, 1985). The system of four-isozymes was probably due to the upstable heterotetramers of either A3Bl or AlB3 (Markert et al. 1975). Therefore, only two LDH-A and LDH-B genes are expressed in lizards as well as other reptiles. Lizard LDH cDNA clones were isolated using a pigeon LDH-B cDNA probe from an oviduct cDNA library. The longest LDH-A cDNA insert of a clone consisted of 1685 bp, including the protein-encoding sequence of 996 nt, 5’ (47 nt) and 3’ (633 nt) UTR, and a poly(A) tail of 9 nt (GenBank accession No. U28410). The longest LDH- B cDNA insert of a clone consisted of 1288 bp, including the protein-encoding sequence of 999 nt, 5’ (58 nt) and 3’ (215 nt) untranslated regions, and a poly(A) tail of 16 nt (GenBank accession No. U28411). The deduced sequence of 332 aa of lizard LDH-A exhibits 97.9% iden- tity with that of chicken LDH-A. The sequence of 333 aa of lizard LDH-B possesses 92.8% identity with that of chicken LDH-B. There is 75.8% identity between the aa sequences of lizard LDH-A and LDH-B. The aa sequence of lizard LDH-A and LDH-B corresponds to isoelectric point of 8.14 and 6.74, respectively. The evolutionary relationships among aa sequences of LDH isozymes from mammals, birds, lizard, Xenopus,