查看文章

Three phospholipase C isozymes (PLC-I, II, and Ill) have been purified from bovine brain. Here, phospholipase C-related cDNA clones corresponding to PLC-I and PLC-III were isolated from a rat brain hgtll expression cDNA library using specific monoclonal antibodies and sequenced. Each of them encodes a distinct polypeptide with a calculated molecular mass of 138,225 (PLC-I) and 85,840 (PLC-III). Comparison of these two with the sequence of another isozyme PLCII (M,= 148,431) that we have previously characterized revealed a low overall sequence homology. Nevertheless, a significant amino acid sequence similarity between the three enzymes was found in two regions, one of about 150 amino acids and the other of about 120 amino acids. The two conserved domains were separated by a variable region. The variable region sequence of PLC-II is relatively long and has recently been shown to contain …