A tomato lipase homologous to DAD1 (LeLID1) is induced in post-germinative growing stage and encodes a triacylglycerol lipase.
A tomato lipase gene homologous to Arabidopsis DAD1 (lipase homologous to DAD1; LeLID1) was cloned and characterized. The corresponding transcript increased rapidly during germination of the seeds and reached a maximum level at four days after germination. Thereafter, it decreased rapidly. Little expression could be found in flowers or fruits. Immunoblot analyses showed that the gene products could be found in the cotyledons and hypocotyls, but not in the roots. In the cotyledons most LeLID1 could be recovered in a soluble fraction. The recombinant LeLID1 protein showed maximum lipase activity at pH 8.0. It showed high activity against triacylglycerols (TAGs) with long acyl chains, but little activity with phosphatidylcholine or monogalactosyldiacylglycerol. TAGs composed of short acyl chains could not be a substrate for the enzyme. A possible involvement of LeLID1 in fat mobilization during seed germination is discussed.
Matsui
Kenji
K
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan. matsui@yamaguchi-u.ac.jp
Fukutomi
Sachiko
S
Ishii
Miho
M
Kajiwara
Tadahiko
T
D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018525:Germination; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000201:enzymology / Q000502:physiology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D010940:Plant Proteins; D011994:Recombinant Proteins; D002265:Carboxylic Ester Hydrolases; D008049:Lipase