A2 globulins

Ceruloplasmin (about 160 kDa) is an a2-globulin. It has a blue color because of its high copper content and... 

Copper appears as the a2-globulin ceruloplasmin in the human body (Sarkar 1994). Deficiency of this protein in serum is characteristic of both Menkes and Wilson s diseases. Wilson s disease is an abnormal storage of Cu(II) in body tissues. Cu(II) in biological material can be determined by spectrophotometry or by FAAS, ceruloplasmin in serum by a spectrophotometric method. 

Yet confusion exists in the literature since authors have not always made a distinction between hemoglobin- and heme-binding plasma proteins. Nyman (N6) and Aber and Rowe (Al) have stressed the difference between these proteins. A recently discovered heme-binding (5-globulin (Nl) [originally called a2-globulin (B6)] with a higher... 

Gold is excreted in both urine and feces but the total amount and proportion excreted by each route bears no constant relationship to each other nor to the plasma gold concentrations. The exact chemical form in which gold circulates in the blood is unknown and may not be identical in every case, even when the same salt is used. Up to 95% of the gold in plasma is protein bound, but whether to albumin (M12), a2-globulin (C7), or a-lipoprotein (L3) is uncertain. The proportion of unbound to protein-bound gold varies in different individuals and in the same individual at different stages of treatment. 

Steroids reversibly bind with two proteins in the plasma corticosteroid-binding globulin, which is a specific a2-globulin and albumin, which has nonspecific activity and a weakly expressed affinity to steroids. 

Fig. 62a, b, and c. Some staining techniques adapted to paper electrophoresis. Sample human serum. Run continuous electrophoresis. The fractions are labeled according to the proposed reference system (see text). The known fractions are +86.20 Albumin +86.18 oij-globulin +86.12 a2-globulin +86.07 3-globulin —86.02 Y-globulin. 

Albumin aj-globulin a2 globulin /3-globulin y-globulin Total protein (g/dL)... 

Ceruloplasmin is an intensely blue glycoprotein of the a2-globulin fraction of mammalian blood, which acts as a copper transfer protein and probably has a role in iron storage. The structure is known it contains three Type 1 (Tl) sites (one of which seems to be inactive) and a Type 2/Type 3 (T2/T3) trinuclear cluster. It is believed to be part of the process of oxidizing Fe(II) to Fe(III) in the transfer of iron from ferritin to transferrin. Reduction of two Tl sites and the T3 pair is fast, but reduction of the T2 Cu site is slow the pathways of electron transfer between the sites have been investigated, but the complete mechanism is still unknown. 

In an extension of these studies, Wada et al. (Wl) reported the incidence of positive precipitation reactions for serum proteins by the Ouchterlony technique to be 77.0% in gastric cancer (26 cases) and 64.5% in chronic gastritis (31 cases). However, this held true in only 15-20% of peptic ulcer cases. In atrophic gastritis, 6-8 precipitation lines were obtained with antisera to human serum and these included intensive lines of albumin and yglobulin and also faint lines of oro-somucoid, a2-globulin, ceruloplasmin, transferrin, and (3-globulin. 

GC protein (group-specific component) is an a2-globulin which is synthesized in the liver and which binds actin released due to hepatocyte decay. Decreased GC-protein values in the plasma are thus attributable both to its reduced synthesis in acute liver failure and its increased binding to actin as a result of hepatocellular disintegration. A value of <34 pg/ml was associated with a lethal outcome in some 70% of cases. 

Because a2 -globulin-induced male rat nephropathy may not be relevant to humans (see Section... 

The peptides are normally formed from a precursor molecule - angiotensinogen - an a2-globulin in the blood, by the action of a 340 amino acid glycoprotein called renin, which acts as an aspartyl protease enzyme (see renin inhibitors). Renin, and its precursor protein, are both stored in the juxtaglomerular cells of the kidney, and release is controlled by three different pathways within the kidney sensitive to Na -transport, blood vessel stretch and Pi-adrenoceptor activation, respectively. Overall, activation of the renin-angiotensin systems is hypertensive, but serves to increase renal perfusion. 

Ceruloplasmin (Cp) is an a2-globulin that contains approximately 95% of the total copper found in serum. Each mol-... 

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