Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_75248 ( "common name" text, "protein name" text, "divergence from human lineage (MYA)" real, "accession number" text, "sequence length (aa)" real, "sequence identity to human protein" text )

### Question ###
What is the accession number of the protein with the common name Purple Sea Urchin?

### Accurate SQL ###

SELECT "accession number" FROM table_75248 WHERE "common name" = 'purple sea urchin'