Kinetics of uptake and activity in mouse liver of glutaminase coupled to desialated orosomucoid.
Desialised orosomucoid (alpha-1-acidic glycoprotein) was coupled to Pseudomonas 7A glutaminase-asparaginase by glutaraldehyde, iodinated and injected into mice. The half-life of radioactivity and glutaminase activity in plasma was about 7 min. Radioactivity and glutaminase activity in the liver reached a peak at about 20 min. The radioactivity in liver then declined with a half-life of about 20 min. Enzyme activity in liver declined with a half-life of about 10 min. The ratio of enzyme activity to radioactivity was lower in the liver than in plasma at all times during the experiment, indicating rapid hepatic inactivation of the enzyme. Uptake into the liver could be blocked by excess desialised orosomucoid. Glutamine levels in the liver were about 10% of normal for 44 min but returned to 50% of normal by 93 min. Intestines, kidney and spleen failed to exhibit any appreciable uptake of desialated orosomucoid glutaminase-asparaginase.
D000818:Animals; D001215:Asparaginase / Q000378:metabolism; D005260:Female; D005971:Glutamates / Q000378:metabolism; D005972:Glutaminase / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D051379:Mice; D009961:Orosomucoid; D011485:Protein Binding; D011549:Pseudomonas / Q000201:enzymology; D012794:Sialic Acids; D013154:Spleen / Q000378:metabolism
D005971:Glutamates; D009961:Orosomucoid; D012794:Sialic Acids; D005973:Glutamine; D001215:Asparaginase; D005972:Glutaminase