Polysaccharide kinase activity of human milk IgG antibodies.
A small fraction of human milk IgG antibodies is shown to possess polysaccharide kinase activity for the first time. Unlike all known kinases, IgG antibodies can use as phosphate donor not only [gamma-(32)P]ATP, but also directly [(32)P]ortho-phosphate. Human milk IgGs therefore possess high affinity to ortho-phosphate (K(m) = 9-71 microM), which is a more effective substrate than ATP. IgG antibodies possessing polysaccharide kinase activity are yet another example of natural abzymes possessing not hydrolytic, but synthetic enzymatic activity.
Karataeva
N A
NA
Institute of Chemical and Fundamental Medicine, Siberian Division of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
Buneva
V N
VN
Nevinsky
G A
GA
D000255:Adenosine Triphosphate / Q000378:metabolism; D000915:Antibody Affinity; D004795:Enzyme Stability; D005260:Female; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000737:chemistry*; D008895:Milk, Human / Q000737:chemistry* / Q000201:enzymology*; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation
D007074:Immunoglobulin G; D010710:Phosphates; D000255:Adenosine Triphosphate; D006026:Glycoside Hydrolases