Mammalian hexokinase 1: evolutionary conservation and structure to function analysis

Genomics. 1991 Dec;11(4):1014-24. doi: 10.1016/0888-7543(91)90027-c.


We have amplified and sequenced the complete coding region of bovine hexokinase isoenzyme 1 (HK1) from brain RNA with PCR primers selected for sequence conservation. The sequence information was analyzed to evaluate the evolutionary and structure-function relationships among the mammalian and yeast HK isoenzymes. Structure to function analysis identified an unduplicated, invariant N-terminal domain involved in HK1 outer mitochondrial membrane targeting, as well as putative carbohydrate and nucleotide-binding sites in the regulatory and catalytic halves of HK1 essential to enzyme function. The ATP-binding site in the catalytic half of the HK1 protein resembles nucleotide-binding regions from protein kinases, with the single amino acid replacement (lysine to glutamate) in the ATP-binding site of the amino half explaining the loss of HK1 catalytic function in the regulatory domain. Sequence comparisons suggest that the 50-kDa mammalian and yeast glucokinases arose separately in evolution. In addition to providing valuable phylogenetic and structure-function insights, this work provides an efficient strategy for rapid cloning and sequencing of the coding regions for other HKs and related proteins.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Biological Evolution*
  • Cattle
  • Cloning, Molecular
  • Hexokinase / chemistry
  • Hexokinase / genetics*
  • Hexokinase / metabolism
  • Humans
  • Isoenzymes / chemistry
  • Isoenzymes / genetics*
  • Isoenzymes / metabolism
  • Molecular Sequence Data
  • Phylogeny
  • Rats
  • Sequence Homology, Nucleic Acid
  • Structure-Activity Relationship


  • Isoenzymes
  • Hexokinase