19338
pH - dependent speciation curves were then calculated using the equilibrium constants determined by potentiometric titration , providing insight into the pH dependence of histidine - metal ion coordination and guiding the design of metal coordination hydrogels .
 Chemical: histidine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: histidine