Markup | Genome Research

Table 1.

Number of Genes Dedicated to Catalyzing Several of the Most Common Post-Translational Modifications

	Yeast	Worm	Human
Protein kinases	∼117^a–120^b	∼381^c–411^e	∼1100^e
Protein phosphatases	∼43^b–52^a	∼106^c–185^e	∼300^e
Ubiquitin system proteins	>50^a	>50^d	>134^a
Glycosyl transferases	>36^a	?	?
Non-proteasomal proteases	∼50^a–75^b	∼194^c	∼700–1000^f

[i] The large number of proteins encoded in a genome catalyzing post-translational modifications suggests that most proteins in the cell will be modified.

[ii] ^a–fThe numbers of genes are taken from (a) the MIPS database, (b) the YPD database of Proteome, Inc., (c) the WormPD database of Proteome, Inc., (d) the Sanger Center WormPep database, (e)Plowman et al. 1999, and (f) Southan 2000.