In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Circulating lysosomal proteases can damage other organs , and measurement of their activity may therefore be of added value in assessing prognosis in this condition .
### Output Text:
Circulating lysosomal proteases can damage other organs , and measurement of their activity may therefore be of added value in assessing prognosis in this condition . 