The stability of l-alanyl-l-tyrosine is affected by various factors. The following are some main aspects:
Temperature: Generally speaking, an increase in temperature will accelerate the degradation or deterioration of l-alanyl-l-tyrosine. In a high-temperature environment, the molecular movement intensifies, which may lead to the breakage of peptide bonds and changes in the structure of amino acids, thus affecting its stability. For example, when it is in an environment above 50°C for a long time, its content and activity may decrease significantly. On the other hand, a low-temperature environment is relatively conducive to maintaining its stability. Usually, under the refrigeration conditions of 2 - 8°C, its structure and properties can be well maintained.
pH Value: The stability of l-alanyl-l-tyrosine varies under different pH conditions. It is relatively stable in a neutral to weakly alkaline environment, and its stability may be affected when the pH value deviates from this range. In a strongly acidic environment, for example, when the pH value is less than 3, the peptide bond may be hydrolyzed, leading to its decomposition. In a strongly alkaline environment, such as when the pH value is greater than 10, the structure of amino acid residues may change, thus affecting its overall stability and biological activity.
Humidity: A high-humidity environment makes l-alanyl-l-tyrosine prone to absorbing moisture. After absorbing moisture, phenomena such as caking and deliquescence may occur, which will not only change its physical properties but also promote the growth and reproduction of microorganisms, accelerate its deterioration process, and reduce its stability. Therefore, it usually needs to be stored in a dry environment to maintain its stability.
Light: High-energy rays such as ultraviolet rays in the light may trigger photochemical reactions of l-alanyl-l-tyrosine, leading to the destruction of its structure or oxidation reactions, thus affecting its stability. For example, when exposed to sunlight or strong ultraviolet radiation for a long time, its color may change, and its activity will also decrease. Therefore, it generally needs to be stored in a light-proof container to reduce the impact of light on its stability.
Oxygen: The amino acid residues in l-alanyl-l-tyrosine contain groups that are easily oxidized, such as the phenolic hydroxyl group in the tyrosine residue. In an aerobic environment, these groups are easily oxidized, thus changing the structure and properties of the molecule and affecting its stability. To reduce the impact of oxygen, products usually adopt sealed packaging, or substances such as antioxidants are added to the packaging to improve its stability.
Metal Ions: Certain metal ions, such as copper ions and iron ions, may catalyze l-alanyl-l-tyrosine to undergo oxidation or other chemical reactions, reducing its stability. For example, copper ions can undergo a complexation reaction with tyrosine residues, which in turn triggers a series of changes unfavorable to stability. Therefore, during the production and storage processes, contact with these metal ions should be avoided as much as possible.
Microorganisms: If l-alanyl-l-tyrosine is contaminated by microorganisms, various enzymes and metabolites will be produced during the growth and metabolism of microorganisms. These substances may decompose it or change the environmental conditions in which it is located, thus affecting its stability. Therefore, maintaining the cleanliness and hygiene of the production environment and storage environment and preventing microbial contamination are crucial for maintaining its stability.
