A functional update of the Escherichia coliK-12 genome

Table 4 History of distribution of gene product types for E. coli K-12

Gene product type	1993^*	1998^†	2001
Enzyme	748^‡	906	990
Putative enzyme		452	550
Transporter	221	257	310
Putative transporter		281	298
Regulator	164	204	213
Putative regulator		168	151
Membrane		37	47
Putative membrane		55	132
Factor	36	68	109
Putative factor		52	33
Structure	113^§	83	90
Putative structure		58	35
Carrier		17	35
Putative carrier		6	25
Extrachromosomal origin		56	282
Putative extrachromosomal		15
Phenotype	314	148	98
RNA	104	112	116
Putative RNA		4
Leader		12	12
ORF		1,413	886
Total	1,700	4,404	4,412^¶

^*Adapted from Riley [24]. ^†Data from July 1998 record of GenProtEC. ^‡Includes enzymes, leader peptides and enzyme activity. ^§Includes membrane components. ^¶This number includes overlap situations where modules of a gene belong to different gene product type categories. The total number of genes is 4,401.

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