In the process of freeze-drying, because protein hydration layer was removed, priority mechanism no longer apply.
For the protection mechanism of the lyophilizer, still in the study, at present there are two main types:
1)
Water alternative hypothesis: many researchers believe that because there are a lot of hydrogen bond in the protein molecules, combined water through hydrogen bonding with the protein molecule.
When protein lost moisture, in the process of freeze-drying protective agent of hydroxyl can replace protein hydroxyl groups on the surface of the water, to form a layer on the surface of protein assumes that the hydration of the membrane, which can protect the hydrogen bonding of the connection position does not directly exposed to the surrounding environment, advanced structure, stable protein prevents the protein denaturation by lyophilization, make it even in the case of low temperature freezing and drying water loss and still maintain the integrity of the protein structure and function.
2)
Glassy state hypothesis: the researchers think that in the drying process of solution containing protective agent, when the concentration is large enough and the crystallization of protective agent does not occur, protective agent -
Water mixture will vitrification.
Study found under the glass state, the behavior of the material both solid and fluid, high viscosity, it is not easy to crystallize, and molecular diffusion coefficient is very low, thus has sticky protectant surrounded around protein molecules, forming an ice is similar to that of a glassy structure of carbohydrates vitreous body, make the macromolecule
material chain of forging, to prevent the spread of protein and precipitation, maintain the stability of the three-dimensional structure of protein molecules, so as to protect.
at present most of scholars agree & quot;
Water alternative hypothesis & quot;
Because the protein can be detected through the experiment and hydrogen bonding between protective agent, to provide theoretical evidence.
In fact, whether & quot;
Water alternative hypothesis & quot;
Or & quot;
Glassy state hypothesis & quot;
, they are based on the basis of the solution implements some or all of the vitrification freezing.
the lyophilizer:
