Antifreeze protein is a kind of protein or glycoprotein that can inhibit the growth of ice crystals. Since its discovery in the 20th century, the research object has shifted from polar fish and insects to plant materials.

Polygonum viviparum (Polygonum viviparum), which grows at an altitude of 3 450 m in Tianshan Mountain, was used as experimental material to extract apoplast proteins from leaves. By SDS-PAGE analysis, it was found that the molecular weight of seven peptides ranged from 65 438+05.2 KD to 72.3 KD, and PAS staining showed that all of them contained glycosyl groups. Light microscope tissue sections showed that the extracellular body of Polygonum viviparum leaves was rich in protein, and PAS staining confirmed that it contained glycoprotein. By measuring its thermal hysteresis value, it is further confirmed that apoplast protein is a glycoprotein with antifreeze activity, which shows that antifreeze protein is an important material basis for maintaining the frost resistance of Polygonum viviparum.

The antifreeze protein AFP was found by the method of ice affinity purification. The researchers found that when low temperature leads to crystal formation, protein will be activated and added to prevent crystal lattice formation. Once the temperature increases or the pH value decreases, the antifreeze protein will completely lose its activity.