I am working on MTRR gene and i have specific primers from some article but i do not know what is the size that should i obtain ?
for a successful reaction , really i have PCR products and relatively all of them have the same size but i would like what is the specific size that should produce from those primers that i have ?
please help me

you will have to look at/download the cDNA sequence of your gene from pubmed and do an alignment of the primers.

the length between the beginning of your upstream primer and your downstream primer will determine the size of the PCR product.

you can download vector NTI 10 from Invitrogen if you are an academic user.

https://catalog.invitrogen.com/index.cfm?fuseaction=userGroup.userGroupHome&CFID=37373091&CFTOKEN=f42a26459f7e979f-4455DED8-5056-AC31-DA9C22E57345EF8F

and pubmed you will have access to, since you have internet.

alternatively, you could do a BLAST search with the primer sequence on pubmed.

and what is the PCR template you are using? is that cDNA or genomic DNA?

genomic DNA