Albumin nitrogen content

Calibration of Total Protein Methods Bovine or human albumin is commonly used to calibrate biuret methods. Albumin has been prepared consistently in high purity, it contains only amino acids, its nitrogen content is a constant fraction of its molecular mass, and the number... 

While it cannot be denied that the soundest methods for the estimation of pure albumin in aqueous solution are likely to be those based on elementary composition (i.e., carbon or nitrogen) or measurement of peptide bonds (e.g., far-ultraviolet spectrophotometry) the oft-repeated statement that the Kjeldahl nitrogen method for determining plasma proteins is theoretically more sound than others is untrue. This method suffers no less than others from the disadvantage that the individual plasma proteins possess different nitrogen contents (Table 3). 

Nitrogen Content of Human Plasma Albumin and Globulins ... 

The biuret method The bimet method is a colorimetric technique specific for proteins and peptides. Copper salts in alkaline solution form a pruple complex with substances containing two or more peptide bonds. The absorbance produced is proportional to the number of peptide bonds that are reacting and therefore to the number of protein molecules present in the reaction system. Thus, the biuret reaction with proteins is suitable for the determination of total protein by spectrophotometry (at 540-560 nm). The method is used extensively in clinical laboratories, particularly in automated analyzers in which protein concentration can be measured down to 0.1-0.15gl. The use of bovine or human serum albumin to standardize the biuret method is well established. ITigh-purity albumin contains only amino acids its nitrogen content is a constant fraction... 

The Hexose, Hexosamine, Acetyl and Amide-Nitrogen Content of Hen s Egg Albumin, Biochem. J. 77, 239-247 (1960). 

It has been reported that in normal individuals who eat a standard breakfast there is no significant change in blood urea nitrogen, carbon dioxide content, chloride, sodium, potassium, calcium, phosphorus, total protein, albumin, creatinine, uric acid, cholesterol, and cholesterol esters (A4). It should be emphasized again that the effects of fasting are quite different in normal, healthy persons than in sick people. 

A significantly higher amoimt of protein is found in beans from South Africa compared to beans from Botswana. The amount of protein in beans from Namibia is between the contents from the two other countries (Holse et al., 2010). The variation in protein content might be due to different concentration of nitrogen in the soils. Bower et al. (1988) found that globulins are the most abimdant (53%) protein constituents in morama beans. The beans furthermore consist of albumins (23.3%), prolamins (15.5%), alkali soluble glutelins (7.7%), and acid-soluble glutelins (0.5%). 

Various etiologies produce differing biochemical pictures. " Determination of serum content of calcium (albumin corrected), phosphorus, alkaline phosphatase, urea nitrogen, creatinine, PTH, 25(OH) vitamin D, and calcitriol, as well as urinary calcium, creatinine, and phosphorus, can help in determining the cause, deciding on treatment, and monitoring efficacy of therapy. Definitive diagnosis is by bone biopsy. 

Blood and urine samples are often collected after the patient has fasted for a period of time (e.g., overnight), particularly for cholesterol or glucose analysis. One study indicates that an average breakfast has no significant effect on the concentration of the blood content of carbon dioxide, chloride, sodium, potassium, calcium, urea nitrogen, uric acid, creatinine, total protein, and albumin. Serum phosphorus is slighdy depressed at 45 min after the meal but not after 2 h. 

Egg-albumin, with a content in formaldehyde nitrogen of 24 per cent, gives 3.6 per cent of ammoniacal nitrogen when the catalyst used is pepsin, and only 1.4 per cent when trypsin is used. Similar results are obtained with the other albuminoids. 

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