Description
Midkine (MK, MDK), or Neurite Growth-promoting Factor 2, is a basic heparin-binding growth factor of low molecular weight, a member of the NEGF family whose founding member is pleiotrophin (NEGF1, 46% homologous with MK). It is a nonglycosylated protein, composed of two domains held by disulfide bridges. It is a developmentally important retinoic acid-responsive gene product strongly induced during mid-gestation, hence the name midkine. Restricted mainly to certain tissues in the normal adult, it is strongly induced during oncogenesis, inflammation and tissue repair