Crude protein factor

If it is required to perform the determination by digestion and distillation, refer to Method 5.6b. Determination of organic plus ammonium-N by digestion and distillation, but use 2 g oven-dry plant sample ground to 1 mm. Also, for the calculation, multiply the sample titre minus blank titre by 0.35 to give the % N in the sample. Multiply the % N by 6.25 to get the % crude protein. This assumes there are 160 g N kg- plant protein. Traditional factors for other products are almonds, 5.18 brazil nuts and peanuts, 5.46 coconuts and tree nuts, 5.30 dairy products, 6.38 wheat, 5.7. Note about 20% of any nitrate present will be included. 

Analytical Procedures (24). Crude protein analyses on the combined solid/ liquid fraction of the 0- and 48-h postinoculation samples were performed using carbon-hydrogen-nitrogen analysis (25) with a protein conversion factor of 6.25 x nitrogen content. 

To estimate crude protein content of biomass or other materials, the nitrogen content of the material is measured by Kjeldahl or combustion methods and multiplied by a conversion factor where ... 

We have reported that bulbs of Crocus sativus contain a poly-histidine protein factor, which aggregates human platelets in vitro. The molecular weight of this factor as found by gel filtration chromatography on a Sephadex G-75 column and sodium dodecylsulfate (SDS) polyacrylamide slab gel electrophoresis is 42,000Da [79], In addition, another low molecular weight protein factor isolated from the same crude extract was found to inhibit human platelet aggregation in vitro [80]. The effect of Crocus sativus on blood coagulation has been also examined by Nishio et al [81]. 

The chemical nature of crude protein in feedstuffs is the primary factor determining how rapidly it is degraded to ammonia or escapes microbial degradation. To compare feedstuffs, feed nitrogen can be divided into NPN, true protein, and unavailable fractions, which Pichard and van Soest (1977) labeled as the A, B, and C fractions, respectively (Fig. 18.3). The A fraction is rapidly attacked by rumen bacteria and converted to ammonia. Approximately 20% of the crude protein in SBM is in the A fraction and is degraded in the rumen at a rate of 300%/h (NRC, 1996). In contrast, a more undegradable protein source like distillers grains has 6% of the crude protein in the A fraction. 

Values are moisture and ash free crude protein is calculated fromKjeldahl nitrogen with the factor 6.25. Identified by infrared G - gutta, R - rubber, W - wax. 

The methods for the reconstitution of nuclear protein import in vitro using permeabilized cells and crude cytosolic extracts have been presented previously (Adam et ai, 1991). Here we go one step further and describe methods for the production of the essential protein factors that make it possible to reconstitute nuclear protein import in a purified system consisting of the karyophile to be studied, permeabilized cells, and pure recombinant proteins in a defined buffer system. This represents the current minimal system for faithful reconstitution of nuclear protein import and"is the starting point for further characterization of the transport pathway and the identification of other nuclear components essential for nuclear protein transport and accumulation. 

The total nitrogen content of the sample is determined after either reduction of all nitrogen to ammonia or liberation of all nitrogen as nitrogen gas. The crude protein content of the sample is derived from the ammonia/nitrogen content by use of appropriate conversion factors. In the case of meat and meat products, the factor 6.25 is used to convert ammonia/nitrogen to crude protein, on the basis that 16% of protein is nitrogen. 

This amount corresponds to the inhibitor isolated from 3 gm of fresh tissue (trunk of chick embryo) 700 fig of DNA corresponds to the amount DNA obtained from about 3 gm of tissue. Inhibition of the vegetalizing factor is observed only in the presence of the inhibitor fraction from chick embryos or DNA, not in the presence of polyanions such as tRNA, double-stranded homo- and heteropolymeres of nucleotides or polysaccharides. The neuralizing activity of the crude protein is not inhibited by DNA (not shown in the table). 

Interestingly, in reticulocyte lysates, the effect of ds RNA is similar to that resulting from heme deficiency (63), that is, polypeptide chain initiation is inhibited. (For an extensive discussion, see chapter 10 of this book).. The ds RNA appears to induce a protein kinase which phosphorylates initiation factor eIF-2 (63). Experiments in our laboratory (M. Jaye, unpublished data) have failed to detect the presence of any phosphorylated components in the crude initiation factor preparation after virus infection corresponding to those elicited in the presence of ds RNA. 

HELENTJARIS, T. and EHRENFELD, E. Control of protein synthesis in extracts from poliovirus-infected cells. I. mRNA discrimination by crude initiation factors. J. Virol. (1978),... 

Table 13.1 Factors for converting nitrogen to crude protein...

Brewers yeast, which is usually dried (the fresh form spoils quickly), is the nonfermentative, nonextracted yeast of the botanical classification, Saccharomyces, derived as a byproduct from the brewing of beer and ale. It is used primarily as a rich supplemental source of the B vitamins and unidentified factors. It is also an excellent source of protein (it contains a minimum of 35% crude protein) of good quality. 

Dried torula yeast is an excellent source of high-quality protein (50 to 62% crude protein), minerals, B vitamins (including vitamin B-12), unidentified factors, and of vitamin D if irradiated. Unlike the bitter-tasting brewers yeast, torula yeast is tasteless, thereby facilitating its use as a palatable foodstuff. Torula yeast is available in powder and tablets. 

Van Steeg, H., Thomas, A., Verbeck, S., Kasperaitis, M., Voorma, H. O., and Benne, R., 1981a, Shut-off of neuroblastoma cell protein synthesis by Semliki Forest Virus Loss of ability of crude initiation factors to recognize early Semliki Forest Virus and host mRNAs, J. Virol. 38 728. 

Overall these results suggest that greater choline supply seems to be helpful in optimising milk production in dairy cows, even though other factors such as dietary composition, dietary crude protein content and post-ruminal methionine supply merit further investigations. 

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