ATP:guanido phosphotransferases are a family of structurally and functionally
related enzymes [1,2] that reversibly catalyze the transfer of phosphate
between ATP and various phosphogens. The enzymes that belongs to this family
are:
- Creatine kinase (EC 2.7.3.2) (CK) [3,4], which plays an important role in
energy metabolism of vertebrates. It catalyzes the reversible transfer of
high energy phosphate from ATP to creatine, generating phosphocreatine and
ADP. There are at least four different, but very closely related, forms of
CK. Two of the CK isozymes are cytosolic: the M (muscle) and B (brain)
forms while the two others are mitochondrial. In sea urchin there is a
flagellar isozyme, which consists of the triplication of a CK-domain.
- Glycocyamine kinase (EC 2.7.3.1) (guanidoacetate kinase), an enzyme that
catalyzes the transfer of phosphate from ATP to guanidoacetate.
- Arginine kinase (EC 2.7.3.3), an enzyme that catalyzes the transfer of
phosphate from ATP to arginine.
- Taurocyamine kinase (EC 2.7.3.4), an annelid-specific enzyme that catalyzes
the transfer of phosphate from ATP to taurocyamine.
- Lombricine kinase (EC 2.7.3.5), an annelid-specific enzyme that catalyzes
the transfer of phosphate from ATP to lombricine.
- Smc74 [1], a cercaria-specific enzyme from Schistosoma mansoni. This enzyme
consists of two CK-related duplicated domains. The substrate(s) specificity
of Smc74 is not yet known.
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