Protein with papain

Pish protein concentrate and soy protein concentrate have been used to prepare a low phenylalanine, high tyrosine peptide for use with phenylketonuria patients (150). The process includes pepsin hydrolysis at pH 1.5 ptonase hydrolysis at pH 6.5 to Hberate aromatic amino acids gel filtration on Sephadex G-15 to remove aromatic amino acids incubation with papain and ethyl esters of L-tyrosine and L-tryptophan, ie, plastein synthesis and ultrafiltration (qv). The plastein has a bland taste and odor and does not contain free amino acids. Yields of 69.3 and 60.9% from PPG and soy protein concentrate, respectively, have been attained. 

Heavy meromyosin (HMM molecular mass about 340 kDa) is a soluble protein that has both a fibrous portion and a globular portion (Figure 49-4). It exhibits ATPase activity and binds to F-actin. Digestion of HMM with papain generates two subfragments, S-1 and S-2. The S-2 fragment is fibrous in character, has no ATPase activity, and does not bind to F-actin. 

A family of 100 hybridoma antibodies can typically provide 20 tight binders and these need to be assayed for catalysis. At this stage in the production of an abzyme, the benefit of a sensitive, direct screen for product formation comes into its own. Following identification of a successful catalyst, the antibody is usually recloned to ensure purity and stabilization of the clone, then protein is produced in larger amount (—10 mg) and used for determination of the kinetics and mechanism of the catalysed process by classical biochemistry. Digestion of such protein with trypsin or papain provides fragment antibodies, Fabs, that contain only the attenuated upper limbs of the intact IgG (Fig. 1). It is these components that have been crystallized, in some... 

For the SAXS studies a CBH II sample was prepared by affinity chromatography from r. reesei QM 9414 to give the enzyme in a homogeneous form 27. In SDS-PAGE the protein had a size of 58 kDa and the isoelectric point was 4.9. Glycosy-lation was estimated as 8 to 18 % 36. The molar absorptivity at 280 nm was 75 000 M xm To obtain the core protein partial proteolytic hydrolysis with papain was per-... 

Pantothenic acid occurs in foods both in the free form and bonded to coenzyme (CoA) or acyl carrier protein (ACP) therefore hydrolysis is needed to extract it totally. Since it is degraded by acid and alkaline hydrolysis, only an enzymatic digestion can be applied. Enzyme hydrolysis with papain, diastase, clarase, takadiastase, intestinal phosphatase, pigeon liver pantetheinase, or combination of them has been used. 

The ability of coordinated NO to react with thiols has led to the suggestion of an alternative mechanism for activating guanylate cyclase. This involves nitroprusside oxidation of protein sulfhydryls to cross-link the protein with a disulfide bridge. For example, papain, which has an essential cysteine (cys-25) and glyceradehyde-3-phosphate dehydrogenase (cys-149) are both inhibited by nitroprusside with formation of [Fe(CN)5(NO)] and [Fe(CN)4NO] [132]. The suggested anaerobic reaction is ... 

Sekul et al. (29) studied the nitrogen solubility properties of enzyme-hydrolyzed peanut proteins. A deionized water dispersion of peanut flour (1 10, w/v) was treated with papain (0.5% total volume) at 45OC for 15 min. Solubility was tested over a range of pH 1 to 9. In general, papain treatment improved solubility at all levels examined except pH 2 and 8 (Figure 6). 

Endogenous biotin in foods is predominately protein bound and is relatively stable (180). Consequently it can be extracted under fairly harsh conditions, e.g., autoclaving in 4 M sulfuric acid for 2 hours at 120°C. Enzymatic hydrolysis with papain will also release biotin from proteins (181). Potential sample-cleanup procedures include adsorption on charcoal and/or ion-exchange chromatography (182,183). 

Enzyme hydrolysis, with papain, diastase, clarase, takadiastase, intestinal phosphatase, or combinations thereof is most commonly used to release pantothenate from food proteins (186). A cold perchloric acid extraction was used to release pantothenic acid from tissue samples (187). Food spoilage prior to analysis may lead to inflated pantothenic acid levels (19). 

Most of the experiments on incorporating amino acid esters into proteins during the plastein reaction have been carried out with papain, indicating that it is one of the best enzymes for this purpose. Other enzymes such as chymotrypsin (40) or carboxypeptidase Y from Sac-charomyces cerevisiae (41) are potent catalysts for peptide synthesis in homogeneous systems using N-acylamino acid esters of peptides as substrates and amino acid derivatives or peptides as nucleophile components. Adding organic co-solvents favored peptide bond synthesis (42,43). 

Proteinaceous Surfactants Prepared by Covalent Attachment of L-Leucine / -Alkyl Esters to Food Proteins by Modification with Papain... 

Covalent Attachment of a Lipophilic Nucleophile to a Hydrophilic Protein with the Use of Papain... 

Succinylated FPC treated with papain for 30 min in the absence of L-leucine 71-alkyl ester. Similar notations are used for the hydrolysates of other succinylated proteins. 

To establish the amino acid sequence unequivocally it is necessary to have peptides with overlapping sequences. This may be accomplished by determining the sequence of fragments obtained from treating a second aliquot of the protein with chymotrypsin. If these fragments are then treated with trypsin as a check, peptides identical to those obtained previously by successive treatment with trypsin and chymotrypsin are obtained. Other proteolytic enzymes, such as pepsin, subtilisin, and papain, with wider specificity than trypsin and chymotrypsin have proved useful in sequencing of some proteins. 

Industrial Uses. Papain is used in the leather industry to prepare the sides for tanning. Its proteolytic action removes some of the undesirable proteins which adhere to the hide and thus facilitates the subsequent tanning process. In the textile industry, the treatment of wool fibers with papain has been found to reduce the shrinkage from laundering. This appears to be caused by the abihty of the enzyme to destroy the elastic properties of wool protein. Because of its digestive action on protein, papain is used as a spot remover in the laundry and dry cleaning business. 

Several proteolytic enzymes have a broad substrate specificity, but none are known which will hydrolyze all of the types of peptide bonds found in proteins. The S. griseus proteinase, papain, and the subtilisins extensively hydrolyze most proteins with liberation of free amino acids, but each enzyme also leaves many peptide bonds intact. For total enzymatic... 

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