It has been shown [1,2,3] that the following carbohydrate and purine kinases are evolutionary related and can be grouped into a single family, which is known [1] as the 'pfkB family':

• Fructokinase (EC 2.7.1.4) (gene scrK).
• 6-phosphofructokinase isozyme 2 (EC 2.7.1.11) (phosphofructokinase-2) (gene pfkB). pfkB is a minor phosphofructokinase isozyme in Escherichia coli and is not evolutionary related to the major isozyme (gene pfkA). Plants 6-phosphofructokinase also belong to this family.
• Ribokinase (EC 2.7.1.15) (gene rbsK).
• Adenosine kinase (EC 2.7.1.20) (gene ADK).
• 2-dehydro-3-deoxygluconokinase (EC 2.7.1.45) (gene: kdgK).
• 1-phosphofructokinase (EC 2.7.1.56) (fructose 1-phosphate kinase) (gene fruK).
• Inosine-guanosine kinase (EC 2.7.1.73) (gene gsk).
• Tagatose-6-phosphate kinase (EC 2.7.1.144) (phosphotagatokinase) (gene lacC).
• Escherichia coli hypothetical protein yeiC.
• Escherichia coli hypothetical protein yeiI.
• Escherichia coli hypothetical protein yhfQ.
• Escherichia coli hypothetical protein yihV.
• Bacillus subtilis hypothetical protein yxdC.
• Yeast hypothetical protein YJR105w.

All the above kinases are proteins of from 280 to 430 amino acid residues that share a few region of sequence similarity. We have selected two of these regions as signature patterns. The first pattern is based on a region rich in glycine which is located in the N-terminal section of these enzymes; while the second pattern is based on a conserved region in the C-terminal section.