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: The serum of six affected workers and five controls was tested for autoantibodies that react with human liver cytochrome - P450 2E1 ( P450 2E1 ) and P58 protein disulphide isomerase isoform ( P58 ) .
### Output Text:
The serum of six affected workers and five controls was tested for autoantibodies that react with human liver cytochrome - P450 2E1 ( P450 2E1 ) and P58 protein disulphide isomerase isoform ( P58 ) . 