Peptide and protein mapping by 252Cf-plasma desorption mass spectrometry.

The mapping of peptide digests by using fast atom bombardment mass spectrometry for evaluating the correctness of known or expected protein sequences is a well-established strategy. A similar approach ("PD mapping") is described which utilizes 252Cf-plasma desorption mass spectrometry (PDMS). This PD mapping approach is demonstrated and evaluated by screening the DNA-deduced sequences of recombinant interleukin-2 and human growth hormone. In the PD mapping experiment, the protein is cleaved either chemically or enzymatically and the molecular weights of the peptides predicted from the proposed amino acid sequence are compared with those determined mass spectrometrically. The relatively nondestructive nature of the PD mass spectrometric analysis allows further confirmation of the sequence assignments of individual peptides through additional steps of enzymatic or chemical modification on the nitrocellulose-bound peptides. The PD mapping method is both fast and sensitive, requiring only low nanomole amounts per map.