I suggest that you read about the genetic code to find the codons relevant to your organism.
You'll want to search for codons, perhaps with a tool like fasgrep. You might write your own script if you have a particular output format in mind.
On second glance, it seems that fasgrep is only useful for searching for sequence identifiers, not the sequences themselves.
Depending upon you got these sequence, it is likely that the start and/or the stop codon are missing
BlastX will be able to find a homologous protein sequence based upon the translation of a internal part of your sequence even though it lack the start and stop codon