Patent ID: 6861229

Claim:
A method of identifying a gene product, wherein the method comprises: (a) providing a multiplicity of cells comprising a first gene product; (b) introducing into the multiplicity of cells a library of second nucleic acid sequences encoding second gene products; (c) expressing the second nucleic acid sequences to produce the second gene products such that the first gene product and at least one of the second gene products are secreted from the multiplicity of cells, and the first gene product and at least one of the second gene products contact extracellularly; (d) causing at least one complex to form between the first gene product, an affinity molecule, and at least one of the second gene products; (e) retrieving the complex; and (f) identifying at least one second gene product of the complex, wherein identifying at least one second gene product of the complex comprises: (f1) producing charged fragments from at least a portion of the complex; (f2) detecting the charged fragments by a detector which produces a signal corresponding to the mass-to-charge ratio of the charged fragments and comprises information about the amino acid sequence of at least one second gene product; and (f3) evaluating the signal to identify the at least one of the second gene products.