I really like this new methods chapter from this group!
Sure, KRAS is a small protein (17kDa?) but it's got a ton of different isoforms and some really terrible PTMs (and, arguably, the most important region has 74 lysines in the last 41 amino acids (or something). This chapter walks you through ALL the steps to enrich and analyze a little protein and it's important proteoforms. From the complete instrument settings (they use a QE HF + BioPharma, but on a protein this size, you can use just about anything with minor adjustments) through step-by-step analysis with the free ProSite Lite software (and XCalibur), there aren't room for too many questions.