Table 1. Description and categorization of biological metrics.

Metric Level	Metric	Short Name
Protein Metrics	Gene Ontology: Molecular Function	F
	Gene Ontology: Biological Process	P
	Gene Ontology: Cellular Compartment	C
Site Metrics	Pfam Domains	Pfam
	Domain Phosphorylation	Pfam Site
	PhosphoELM Kinase Annotations	PELM Kinase
	Linear sequences	Motifs
	Scansite Kinase Predictions	Scansite Kinase
	Scansite Binding Predictions	Scansite Bind
Dynamic Quantitative Metrics	Minimum Phosphorylation	MinValue
	Maximum Phosphorylation	MaxValue
	Maximum Positive Change	MaxPosChange
	Maximum Negative Change	MaxNegChange

There are a total of nine biological metrics and four dynamic metrics analyzed for enrichment in clusters. The metrics tested describe information regarding the protein a peptide arises from, the particular site of phosphorylation, or the quantitative data. The abbreviated labels used throughout this work are given.