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: Out of these 67 proteins , LID significantly changed the expression level of five proteins : alphabeta - crystalin , gamma - enolase , guanidoacetate methyltransferase , vinculin , and proteasome alpha - 2 subunit .
### Output Text:
Out of these 67 proteins , LID significantly changed the expression level of five proteins : alphabeta - crystalin , gamma - enolase , guanidoacetate methyltransferase , vinculin , and proteasome alpha - 2 subunit . 