Hide Powder

Haut-krankheit, /. skin disease, -krebs, m. cancer of the skin, epithelioma, -lehre, /. dermatology, -leim, m. glue (or size) from hides, -pulver, n. hide powder, -reaktton /,... 

Starch (1), Cellulose (2), Cellulose Methyl Ether (3), Oxy-cellulose (4), PVA (5), Partially Hydrolyzed PVAc (6), Silk (.2), Wool (7), Hide-Powder (8), Natural Rubber Latex ( ), Synthesized Poly-(ot-Amino Acids) (10), Nylon-6 (11), Nylon-3 (12), Ot-Amylase (13), Lysozyme (14), RNA (15), Polyacrylonitrile (16), Polyvinyl-sulfonate (17) ... 

General protease, a-amylase, and exoglucanase activities were estimated using hide powder-, amylose-, and celliilose-azure substrates, respectively, as described earlier (49). Here, standard curves were developed for the hydrolysis of each azure-linked substrate by standard enzymes of known activity. By this method, one cellulose-azure hydrolysis unit corresponds to one filter paper unit, one unit of hide powder-azure activity corresponds to the hydrolysis of 1.0 nmole of iV-benzoyl-L-tyrosine ethyl ester (BTEE) per min, and one amylose-azure unit of activity corresponds to the hydrolysis of 1.0 nmole of maltose from starch per 30 min. 

White or yellowish-white, woolly powder, prepared from the best quality of hide from which the hair has been removed with lime and which has been thoroughly washed. Hide powder should have but a slight odor and should lie specially free from odors of decomposition products. It is used for tannin determination. 

As the quantity of water-soluble constituents in the various hido powders varies greatly, it is always necessary, before using a hide powder for tannin determinations, to determine the quantity of soluble constituents by a blank test according to the method described here. 

Non-tanning Matters.—For this determination, the tanning substances are absorbed from the solution by hide powder, the liquid being then filtered and the dry residue estimated in the filtrate. The detanning of the solution may be effected by one of the two following methods. 

The bell is then placed in a beaker a of about 200 c.c. capacity so that the covered mouth of the bell almost touches the bottom of the beaker. Into the latter a little of the tanning solution is poured and when this has all been sucked up by the hide powder (usually in about an hour), the beaker is filled with the tanning solution and the siphon filled with the liquid by suction at its free end. The liquid flows slowly from the siphon so that the efflux of about 100 c.c. requires 1-5-2 hours. 

Various qualities of hide powder have been recommended for this determination in general, a powder answering the requirements already indicated for the preceding method may be employed. Also in this case some prefer to use a chromed hide powder, which will give more concordant results. 

Hide powder this should be white, woolly and free from any substances soluble in cold water and capable of reducing permanganate—this is shown by a blank test. 

To 10 c.c. of the tanning solution prepared in the above conditions are added 20 c.c. of the indigo solution, the mixture being then diluted with three-quarters of a litre of water and titrated with permanganate, as already described, to a distinct golden-yellow colour. To another quantity of 50 c.c. of the same solution are added 3 grams of hide powder after about 18 hours, during which time it is occasionally shaken, the liquid is filtered and 10 c.c. of the filtrate titrated in the same conditions as before. 

With tanning extracts adulterated with cellulosic extracts, the indirect method does not, however, give reliable results, since cellulosic extracts contain non-tannins which are fixed by the hide powder. In such a case the tannin should be determined by the direct method, since these non-tannins have no appreciable action on permanganate the difference between the results of the two methods will give an approximate indication of the extent of the adulteration, if this is at all marked. 

Another quantity of 500 c.c. of the filtered aqueous solution (corresponding with 10 grams of the leather) is concentrated to 125 c.c., in which the soluble non-tannins are determined by means of hide powder, as described for tanning substances (see p. 340). Subtraction from the result of the amount of the soluble mineral matter gives the soluble organic non-tannins. 

High-molecular-weight solid substrates such as hide powder azure, and cellulose, chitin, and agar stained with remazol brilliant blue R have been used in enzyme assays to investigate activities in extracts from sediments (Reichardt, 1986). This technique is one of the few means of examining the particle — dissolved transition in relationship to sedimentary enzyme activity, but the necessity of extracting enzymes from sediments complicates interpretation of the results, because extraction efficiency, as well as the... 

Sample Test Transfer about 2.0 g of sample, accurately weighed, into a 500-mL volumetric flask, and dissolve in and dilute to volume with water. Transfer 100 mL of this solution into a 300-mL Erlenmeyer flask, and add 7.2 g of Hide Powder (L. H. Lincoln Son, Inc., or equivalent). Shake the flask for 20 min, let it stand for 20 min, and filter through a G4-filter, or equivalent. The filtrate should be clear. Pipet 50 mL of the filtrate into a tared crystallizing dish. Evaporate to dryness on a steam bath, and heat in an oven at 105° for 1 h. Cool in a desiccator, weigh, and calculate the weight difference. 

Blank Test Perform a blank test on each lot of Hide Powder. Transfer 7.2 g of Hide Powder EFT, accurately weighed, into a 300-mL Erlenmeyer flask containing 100 mL of water. Proceed as directed in the Sample Test, beginning with Shake the flask for 20 min.. .. Calculate the weight difference. 

The dyed proteins, though also not very cheap, are much more suitable from an economical point of view. The use of insoluble dyed proteins (e.g. hide powder azure) is very simple and handy. After the chosen reaction time the insoluble protein is removed by filtration or centrifugation and the absorbance of the filtrate is immediately measured. For instance, Rinderknecht proved that it was possible to determine trypsin activity with HPA (hide powder azure) in ng quantities per ml and proteolytic activities in biological materials, tissue extracts, serum, urine, faeces, etc. Other authors applied this substrate for assaying proteolytic activity in beer stabilized with chillproofing preparations containing proteases (mainly papain)... 

Dry the hide powders in an oven for 16 h and cool in a desiccator. Add 1 ml of 3% chrome alum CrK(SO )2 solution for each gram of air-dried hide powders at 25 2 °C for 2 h. Wash the pretanned hide powders thoroughly with water at 25 2 °C. Filter the suspended hide powders and squeeze the powders to obtain about 75% of the moisture in the powders. Weigh 50 g of the wet hide powders (containing approximately 75% moisture), equivalent to 12.5 0.3 g of dried powders, and add them to a 200 ml volumetric flask. Fill the flask with testing solution to the 200 ml mark. Close the bottle and keep the solution at 25 2 °C for 15 min. Filter the solution immediately into a beaker containing 2 g of kaolin. 

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