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: HOMER1 is a protein with pivotal function in glutamate transmission , which has been related to the pathogenesis of these complications .
### Output Text:
HOMER1 is a protein with pivotal function in <span class="chemical">glutamate</span> transmission , which has been related to the pathogenesis of these complications . 