Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:021525 (albumin)
 60,984 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alpha-D-Mannosidase activity exists in three forms that can be separated by DEAE-cellulose chromatography, alpha-D-Mannosidase was isolated from human kidney in a homogeneous state, and was purified 2100-fold, with p-nitrophenyl alpha-D-mannoside as substrate. The purified alpha-D-mannosidase was practically free from all other glycosidases tested. The Km of the synthetic substrate with the enzyme was 1 X 10(-3) M and the pH optimum 4.5. It was inhibited by heavy metals, sodium dodecyl sulphate, urea and compounds that react with the thiol groups, and was activated by Zn2+, Na+, 2-mercaptoethanol, human albumin and gamma-globulin. The mol. wt. of the enzyme was estimated to be 180 000 +/- 4500. After pretreatment with 2-mercaptoethanol and sodium dodecyl sulphate, alpha-D-mannosidase dissociated into subunits of mol. wts. of 58 000 +/- 600 and 30 000 +/- 380 respectively. Subunits of the same molecular weights were also obtained after the enzyme was heated at 100 degrees C.
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PMID:Isolation and properties of alpha-D-mannosidase from human kidney. 0 43

Phallolysin from the toadstool, Amanita phalloides, is a basic protein that causes direct haemolysis of red cells. The dose-response curve is steep; the pH optimum is in the weakly acid range. The rate of haemolysis increases with the concentration of the lysin, the optimal temperature is 20 degrees C. The percentage haemolysis-time curves are S-shaped. Haemolysis is of the non-osmotic type. Ca2+ is not required but inhibits haemolysis in a concentration-dependent fashion, as do Mg2+ and Zn2+. The red cell sensitivity of various animal species decreases in the following sequence:mouse greater than rabbit = guniea pig greater than rat greater than man greater than dog approximately or equal to pig greater than sheep = cattle. Red cells of cattle and sheep are largely resistant. Phallolysin is virtually not consumed on haemalysis: the amount of haemoglobin released increases with the number of red cells applied; on repeated addition of fresh red cells the haemolysate retains its full activity. Phallolysin is not inhibited by serum, albumin, cholesterol, lecithin, cephalin or sphingomyelin; inhibition by red cell ghosts of phallolysin haemolysis is considerably less than that of digitonin haemolysis. At sublytic concentrations phallolysin, unlike benzalkonium chloride, liberates practically no membrane lipids from human red cells. Surface activity of phallolysin does not exceed that of bovine serum albumin.-A saponin-like interaction with cholesterol as the basic mechanism of haemolysis can be disregarded. There is also no evidence suggesting a detergent-like effect.
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PMID:The haemolytic effect of phallolysin. 0 36

1. Five alkaline ribonucleases (EC 3.1.4.22) were purified about 140- to 1900-fold from human serum by phosphocellulose and DEAE-cellulose chromatographies and Sephadex G-75 filtration, with a total recovery of 22%. These were designated as RNAases 1-5. 2. Optimum activities were observed at pH 8.5-8.7 for RNAases 1-4, and at pH 7.5 for RNAase 5. The molecular weights of these enzymes were estimated by gel filtration as 45 000, 32 000, 20 000, 13 000 and 8500, respectively. 3. These RNAases were found to be heat-labile proteins but are markedly stabilized with bovine plasma albumin. The reaction was activated by Na+, K+, Mg2+ and Ca2+, and inhibited by Co2+, Fe2+, Cu2+ and Zn2+. EDTA had little effect on the velocity of the reaction. Spermine caused 2- to 7-fold activation. 4. Among the substrates examined, these RNAases preferentially hydrolyzed pyrimidine bodies and except for RNAase 5 had a higher affinity for poly(C) than poly(U) as substrate. Each enzyme was free from other nucleolytic enzymes and hydrolyzed only RNA.
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PMID:Purification and properties of alkaline ribonuclease from human serum. 0 40

The increasing awareness of the importance of the divalent cation zinc in normal and pathologic cell functions has prompted our investigations into the mechanism and control of human erythrocyte zinc uptake. The albumin in blood plasma appears to be the main zinc binding moiety, effectively limiting zinc availability ot the red cell. In non-protein and non-phosphate-containing buffers (i.e., bicarbonate or Tris buffer) red cells sequester more than 90% of the extracellular zinc within 10--15 minutes at a rate more than 250 times faster than zink uptake by cells in plasma. In an albumin-containing media, the influx on red blood cell zinc is lightly temperature sensitive (decreased) between 37 degrees C and 25 degrees C, whereas with cells in bicarbonate buffer alone temperature sensitivity does not begin until below 25 degrees C. Over the physiological range, pH variation has a minimal effect on zinc uptake regardless of the media employed. Finally, once associated with the red cell zinc tends to remain, with a zinc efflux less than 2% of influx. We conclude that human erythrocytes are highly permeable to zinc, with the rate and amount of zinc taken up controlled primarily by the zinc binding characteristics of the media in which the cells are suspended.
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PMID:The mechanism and control of human erythrocyte zinc uptake. 2 84

Acid RNase was purified from normal human serum about 2400-fold by chromatography on phosphocellulose and Sephadex G-75 and rechromatography on Sephadex G-75. Assayed with yeast RNA as substrate, the enzyme showed the maximal activity at about pH 6.5 with sodium phosphate buffer. The reaction was activated by Na+, K+, and spermine, but it was not affected greatly by Mg2+, Co2+, and EDTA. Ca2+, Fe2+, Zn2+, and Cu2+ inhibited the reaction. Among the synthetic substrates examined, the enzyme preferentially hydrolyzed pyrimidine nucleotides, with a higher affinity for polycytidylate than for polyuridylate. The enzyme was thermolabile, but it stabilized with bovine plasma albumin. The molecular weight was approximately 15,000, estimated gel filtration on Sephadex G-75, and its isoelectric pH was above 11.0. From normal human leukocytes, acid RNase was purified about 400-fold by the same procedure described previously except that rechromatography on Sephadex G-75 was omitted. The properties of leukocytic RNase were found to be similar to those of serum acid RNase, but the latter enzyme differed in substrate specificity substantially from leukocytic RNase, preferring polyuridylate to polycytidylate. This evidence shows that serum RNase is not of leukocytic origin under normal physiological conditions.
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PMID:Purification and properties of acid ribonucleases in human serum and leukocytes. 2 64

The Acinetobacter spec collagenase has been almost completely purified. This enzyme is a true collagenase the activity of which is high on collagen. The enzyme is active on insoluble collagen, gelatin and the synthetic Pz-peptide, but has no proteolytic activity on casein or bovine serum-albumin. The collagenase was obtained on a simple medium with gelatin and yeast extract. The enzyme was purified by (NH4)2SO4 precipitation. DEAE cellulose column chromatography, Sephadex G 200 gel-filtration. The molecular weight of the enzyme was found to be 102 000 daltons, and its isoelectric point was found to be 7,7 +/- 0,2. The optimum pH and temperature for insoluble collagen hydrolysis were 7.6 and 37 degrees C, respectively; so, this collagenase corresponds to true collagenase. Hydrolysis of Pz-peptide is activated by Ca2+ and inhibited by metal ions (Cu2+, Fe3+, Zn2+, Pb2+, Hg2+). EDTA and o-phenanthroline induced a very significant reduction in enzyme activity. Iodoacetate and p-CMB induced a slight reduction in enzyme activity only at high concentrations (10-2M). The collagenase is most stable for temperatures less than or equal to 50 degrees C.
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PMID:[Purification and physico-chemical properties of collagenase synthesized by a bacterium of the type Acinetobacter sp]. 4 44

The partition of zinc in human serum between two major zinc-binding proteins, albumin and alpha2-macroglobulin, was studied in 28 control subjects and in 156 hospitalized patients. Albumin-bound zinc was both the major and the more dynamic of the serum zinc components. Over a wide range of values the concentrations of albumin-bound zinc and total serum zinc were highly correlated (r=0.91) with each other, as were concentrations of albumin and albumin-bound zinc (r=0.69). alpha2-Macroglobulin-bound zinc was not strongly correlated either with total serum zinc or with the serum concentration of alpha2-macroglobulin. Twenty-four hour urinary excretion of zinc was not correlated with any of the serum zinc parameters. To a large extent it appears that total serum zinc concentration reflects serum albumin concentration.
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PMID:A study of zinc distribution in human serum. 5 52

Lower concentrations of total serum zinc (540 +/- 111 mug/1, mean +/- SEM), and of albumin-bound serum zinc (295 +/- 113 mug/1) and a higher concentration of alpha2-macroglobulin-bound zinc (245 +/- 69 mug/1) were found in 25 patients with decompensated hepatic cirrhosis, compared to 28 healthy subjects (835 +/- 91; 679 +/- 83; 156 +/- 27 mug/1 respectively). Levels of total and albumin-bound zinc were significantly and positively correlated with serum albumin levels. Higher levels of alpha2-macroglobulin-bound zinc were associated with higher levels of alpha2-macroglobulin in these patients (2.8 +/- 0.8 g/1) compared to normals (2.3 +/- 0.6). Hence, not only do decompensated cirrhotics exhibit a lower serum zinc level but a greater proportion of this zinc is associated with the tightly bound, and presumably metabolically more inert, serum fraction. This situation exaggerates the zinc deficiency state of the severe cirrhotic.
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PMID:Distribution of serum zinc between albumin and alpha2-macroglobulin in patients with decompensated hepatic cirrhosis. 5 58

The effect of zinc deficiency on protein synthesis in rats during tularemia was studied. Five weeks prior to infection with the live vaccine strain of Francisella tularensis, rats had been assigned to one of three dietary groups: zinc deficient (-Zn), pair-fed (PF) or ad libitum (AL). Within 4 weeks, zinc deficiency manifested itself by diminished growth rate, decreased serum and liver zinc concentrations and alopecia. By 18 hour post infection, rats of all groups were febrile and exhibited an increased hepatic uptake of zinc. Despite initially lower concentrations of seromucoid in the PF and -Zn groups, infection elicited an increase in seromucoid concentration as well as enhanced incorporation of 3H-leucine into this fraction of comparable degree in all dietary groups. The same held true for ceruloplasmin. Alpha 2-macrofetoprotein also increased to the same extent in all dietary groups. Infection was associated with a decrease in extractable albumin in ad libitum and pair fed control groups. Only the -Zn group showed a significant decrease in specific activity suggestive of diminished albumin synthesis. Zinc deficiency of itself did not cause a decrement in radiolabel in muscle protein. Thus, despite documented zinc deficiency, rats subjected to the stress of infection respond by synthesizing increased amounts of acute phase globulins apparently at the expense of serum albumin and muscle protein synthesis.
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PMID:Protein synthesis in zinc deficient rats during tularemia. 5 80

A geriatric population comprising 585 inhabitants of an institution for the aged was studied. Twenty-six persons with a mean age of 82 years were selected because of skin manifestations suggestive of chronic zinc deficiency. In 10 of the patients a subnormal plasma zinc level was found. This hypozincaemic group underwent a 4 week trial with zinc sulphate tablets, 0.6 g daily. The therapy failed to alleviate the skin condition in any of the patients, thus indicating that the changes were not caused by zinc deficiency. In the hypozincaemic group, plasma albumin was subnormal in all patients and significantly lower than in the normozincaemic subjects. The correlation between plasma zinc and plasma albumin levels in all 34 patients studied was highly significant (rs = 0.69, p less than 0.001). As plasma albumin tends to fall to subnormal concentrations with age, this explains why plasma zinc may be low in the elderly without indicating a state of zinc deficiency. After 2 and 4 weeks' zinc therapy, the mean plasma zinc concentration of the hypozincaemic group rose significantly from 9.5 to 17.6 and 23.4 mumol/1. This increase is higher than the rise observed in younger patients receiving an identical zinc sulphate dosage.
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PMID:Oral zinc therapy in geriatric patients with selected skin manifestations and a low plasma zinc level. 7 97


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