where k is the average number of times a protein is synthesized. The value of k can be estimated as 5 based on the genomic information structure of E. coli (about 3% of E. coli genome is estimated as regulatory information). This is equivalent to that E. coli synthesizes 67 same protein molecules on average at a time. When the bacteria are very small, y is very close to x. The quantity of a kind of protein molecules may be less than 5. In order to ensure at least one protein molecule synthesized at once, the formula needs to be calibrated as: