Table 2. Number and frequencies of PPP, PPG or proline in the five proteomes.

Species	Total number of PPP units	Total number of PPG units	Total number of Prolines	Total number of amino acids	PPP frequency/104 amino acids	PPG frequency/104 amino acids	Proline frequency %
E. coli	100	183	58315	1312586	0.76	1.39	4.44
S. cerevisiae	597	304	111620	2587553	2.31	1.17	4.31
D. melanogaster	5512	2127	408685	7421447	7.43	2.87	5.51
M. musculus	8282	6218	676678	11111878	7.45	5.60	6.09
H. sapiens	9097	6978	693470	10993264	8.28	6.35	6.3

Total number of PPP or PPG units in each proteome was calculated as described in Materials and Methods.