Abstract: In various aspects, the present teachings provide systems, methods, assays and kits for the absolute quantitation of protein expression. In various aspects, the present teachings provide methods of determining the concentration of one or more proteins of interest in one or more samples of interest. In various aspects, the present teachings provide methods of determining the absolute concentration of one or more isoforms of a protein using standard samples of signature protein fragments and parent-daughter ion transition monitoring (PDITM). In various embodiments, the absolute concentration of multiple isoforms of a biomolecule in a sample, multiple proteins in a biological process, a combination of multiple samples, or combinations thereof, can be determined in a multiplex fashion using the present teachings. In various aspects, provided are methods of assessing the response of a biological system to a chemical agent.

Abstract: In various aspects, the present teachings provide systems, methods, assays and kits for the absolute quantitation of protein expression. In various aspects, the present teachings provide methods of determining the concentration of one or more proteins of interest in one or more samples of interest. In various aspects, the present teachings provide methods of determining the absolute concentration of one or more isoforms of a to protein using standard samples of signature protein fragments and parent-daughter ion transition monitoring (PDITM). In various embodiments, the absolute concentration of multiple isoforms of a biomolecule in a sample, multiple proteins in a biological process, a combination of multiple samples, or combinations thereof, can be determined in a multiplex fashion using the present teachings. In various aspects, provided are methods of assessing the response of a biological system to a chemical agent.

Abstract: Synthetic erythropoiesis stimulating proteins are provided. Also provided are methods for synthesizing the proteins. The invention further relates to derivatives of such synthetic erythropoiesis stimulating proteins that are polymer-modified in a defined manner. Methods and uses for such proteins and derivatized proteins are also provided.