Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
what is the subtrate for enzyme ala dehydratase

### Inputs:
table_name: table, columns: ['Enzyme', 'Location', 'Substrate', 'Product', 'Chromosome', 'EC', 'OMIM', 'Porphyria']

### Response:
SELECT Substrate FROM table WHERE Enzyme = ALA dehydratase