Lectins and Toxins
WANG Ke-Yi*, XU Qiang
( Shanghai Institute of Biochemistry, the Chinese Academy of Sciences,
Shanghai 200031, China )
Abstract Although
lectins, in general, are not very toxic, there are some relationships between
lectins and toxins. BEA-type toxins can be divided into two main parts. One
shows sugar-binding activity responsible for targeting. Another part, which
possesses different enzymatic activity, determines the toxicity. The lectins
isolated from Trichosanthes
kirilowii
share some properties with BEA-type toxin, e.g. ricin. Some toxins can
perforate cell membrane, forming an ion channel. A lectin from Pinellia turnata may belong to
this kind of toxin. Several lectins were isolated from snake venom, sharing
homologous amino acid sequences with other components in venom, while a
receptor of well known toxin in venom, phospholipase A2, contains
lectin-like domain. In the venom of Trimeresurus stejnegeri exists a
C-type animal lectin. The conclusion is that both lectins and toxins may be
involved in the defense mechanism of organisms.
Key words lectins； toxins； sugar-binding； enzymes； ion channel
Received: January 10,
2000 Accepted: January 25, 2000
This work was supported by the grant from the National Natural Science
Foundation of China, No. 39570174
* Corresponding author: Tel, 86-21-64374430-264; Fax, 86-21-64338357; e-mail, [email protected]