how to Know the longest ORF in Protein? I have a protein Seq. and I want to know


how to Know the longest ORF in this Protein?


and if there is any tutorial for this process ??
Proteins don't have ORFs, DNA sequences do.  What DNA sequences do you have?  If cDNA (i.e. transcript/mRNA) then an ORF finder will give multiple ORFs and the coordinates on the full-length input DNA which indicate it's length.