Ricin contained in seeds is a heterodimeric glycoprotein [6]. It contains two protein chains with different amino acid sequences, each weighing about 30kDA, and two protein chains are connected by disulfide bonds. In addition, there are two different lengths of sugar molecules connected to it [7]. The two protein chains are as follows:

Chain A contains 267 amino acids [6] and is an N- glycoside hydrolase. This chain will cut the valence bond on rRNA [8] and remove an adenine [6]. Because rRNA is the main component of ribosomes, ribosomes are needed to synthesize protein. When rRNA is destroyed, the synthesis of protein will be inhibited.

The B chain is lectin, and its 262nd residue is bound to the A chain through disulfide bonds [6]. This chain can be combined with galactose residue or mannose residue on the cell surface [9], and the auxiliary chain A enters the cell through the cell membrane to take effect. There are many plants, such as barley, which contain chain A but not chain B, so people who eat a lot of barley will not be poisoned.

Component property

The primary and secondary structures of ricin are clear, and it consists of two chains, A chain is slightly shorter than B chain, and the two chains are connected by a disulfide bond. Contains sugar molecules bound by valence bonds. The main components of sugar are mannose, glucose and galactose. The molecular weight is 66000. In 0. 1 mol galactose solution, the toxin can be stored in the refrigerator for several months without losing its activity, but it is easy to lose its activity after boiling.

Grate toxin