TAMRA vs. Rhodamine B - (Oct/31/2012 )

I would like to order a fluorescence labeled peptide that should go along with Alexa 488 and Alexa 647 labeled antibodies for co-localization. Could you provide me with an suggestion which of the two fluorescence labels would go along best with the antibodies: TAMRA or Rhodamine B? Is there any advantage of one over the other?

Thank you in advance!

I hope you have found the answer to your question. I have another one, related to TAMRA. Does it penetrate cells? I want to use it to label a potential cell penetrating protein. However, if TAMRA penetrates the cells itself, it is not the best label choice then. Thanks in advance! ML