A Globulins

Metabolites of vitamin D, eg, cholecalciferol (CC), are essential in maintaining the appropriate blood level of Ca ". The active metabolite, 1,25-dihydroxycholecalciferol (1,25-DHCC), is synthesized in two steps. In the fiver, CC is hydroxylated to 25-hydroxycholecalciferol (25-HCC) which, in combination with a globulin carrier, is transported to the kidney where it is converted to 1,25-DHCC. This step, which requites 1-hydroxylase formation, induced by PTH, may be the controlling step in regulating Ca " concentration. The sites of action of 1,25-DHCC are the bones and the intestine. Formation of 1,25-DHCC is limited by an inactivation process, ie, conversion of 25-HCC to 24,25-DHCC, catalyzed by 24-hydroxylase. 

The urine frequently contains casts and amorphous debris, but rarely any considerable number of red blood corpuscles. Proteinuria and aminoaciduria are found in nearly all untreated patients from a very early age. The proteinuria is usually reported as albuminuria in the literature, but in some cases the urinary protein has been shown by electrophoresis to consist largely of a-globulin and other relatively low-molecular-weight proteins (B21). A similar urinary pattern occurs in a number of diseases of the renal tubule. The proteinuria is often only moderate in degree, e.g., < 50 to 150 mg protein per 100 ml of urine, but is easily detected by the conventional tests for protein, such as salicylsulfonic acid. Excretion of protein can rise to nearly 1 g/100 ml in some cases (H8, L7). 

The initial report on the nature of sweet potato protein indicated that most of the protein was a globulin "ipomoein"... 

C5a is inactivated by the myeloperoxidase-H202 system, which oxidises a methionine residue (Met 70) on the molecule group A streptococcal endo-proteinases also abolish chemotactic activity of C5a and related compounds. Neutrophil lysosomal enzymes (e.g. elastase and cathepsin G) also destroy C5a chemotactic activity, but as these proteases are inhibited by the serum antiproteinases, a -antiproteinase and a2-macroglobulin, the physiological role of neutrophilic proteases in the inactivation of C5a is questionable. Two chemotactic factor inactivators have been found in human serum an a-globulin that specifically and irreversibly inactivates C5-derived chemotactic factors, and a / -globulin that inactivates bacterial chemotactic factors. These activities are heat labile (destroyed by treatment at 56 °C for 30 min) and are distinct from those attributable to anaphylatoxin inactivator. An apparently specific inhibitor of C5-derived chemotactic activity has also been described in human synovial fluid and peritoneal fluid. This factor (molecular mass of 40 kDa) is heat stable and acts directly on C5a. 

VLDL) comprising apolipoproteins B and E, combined mainly with triglycerides are secreted from the liver. Apo A is an a globulin and apo B is found in the (3 fraction, thus HDL and LDL are sometimes referred to as a and (3 lipoprotein respectively and VLDL because in separation by electrophoresis at pH 8.6, it runs ahead of LDL is called pre- 3 lipoprotein. 

Synonyms Natural latex—milky fluid that consists of extremely small particles of rubber obtained from plants, principally from the Hevea brasiliensis (rubber) tree, dispersed in an aqueous medium. It contains a variety of naturally occurring substances in a colloidal suspension, including about 1% proteins (e.g., a-globulins, hevein), which are the allergenic fraction. ... 

Figure 3.19 — Effect of albumin (A), globulin (B), casein (C), and gelatin (D) on the voltammetric peak of 2 x 10 M acetaminophen, at the tissue (a) and plain (b) carbon-paste electrodes. (Reproduced from [117] with permission of the American Chemical Society).

Acid Casein B Casein A Casein B Casein A2 Casein A2 Casein A2 Casein A globulin A albumin B... 

The three protein pressor substances are renin, a prolonged pressor substance found in shock, and vasoexcitor material. Apparently they are different substances. Renin is the best understood (10). Its reaction with a globulin substrate to form hypertensin or angiotonin suggests that it is a proteolytic enzyme. Renin has been considerably concentrated, but has not been purified. The stimulus for its release by the kidney is a reduction of renal blood flow just how this comes about is unknown. 

Evaporation forces the whole sample rapidly towards a straight and narrow zone at the center. This can easily be observed if the serum sample is stained with a trace of bromophenol blue (V7). Only after some time do the j- and y-globulins migrate backward toward the starting line, while the albumin and a-globulin migrate normally forward for some time (Fig. 5). This migration of the fractions is slower than the first rheophoretic movement. 

Narrowing the surface of application is of only limited value because diffusion is proportional to the square of the concentration or inversely proportional to the square of the width over which the sample is applied. Thus proteins, such as albumins, which are present in large quantity, always tend to diffuse over a broad zone even if the application zone is narrow. This means that large, concentrated samples are not the best for obtaining sharp resolution their use also causes a blurring of the small a-globulin zone which lies quite near to the large albumin fraction. 

Electrophoretic studies (G2, M2) have shown that both types of bilirubin are bound to albumin and sometimes a-globulin. Klatskin and Bungards (K6) found that this binding occurs between pH 6 and pH 9 and that below pH 5 separation occurs almost completely with respect to bilirubin but only partially with the conjugated pigment. This suggests that bilirubin and conjugated bilirubin are attached in different ways to plasma proteins. 

Plasma kinins are tissue hormones liberated from a-globulins of the blood plasma by kallikrein. 

After 4 1/2 hours 1.0 ml. blood contained 1.0 x 105 counts/min. Electrophoretic separation of plasma showed 77% of Cu associated with albumin fractions, 1 to 3% in each a-globulin fraction (total 10%), 1 to 3% in each -globulin fraction (total 10%), and about 3% in y-globulins... 

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