Enzyme-containing granules

The extrusion process is very well established in the plastic and food industry. This technology for the manufacturing of the enzymes-containing granulate combines the advantage of a homogeneous particle size distribution with low-cost ingredients. 

Histochemical studies of bone marrow samples show that peroxidase-containing granules are detectable in promyelocytes. The human promyelo-cytic leukaemia cell line HL-60 grows easily in culture, and the cells resemble promyelocytes both structurally and functionally. Furthermore, they can be induced to differentiate in vitro upon addition of various agents, such as retinoic acid and phorbol esters, and these differentiated cells resemble more mature forms of neutrophils. HL-60 cells possess almost the same amount of myeloperoxidase (4.4 fig per 106 cells) as mature neutrophils, and the enzyme purified from these cells has the same subunit structure. The cells thus actively synthesise the enzyme only until they are induced to differentiate. This cell line has been extensively used to study the molecular events controlling the expression of enzymes such as myeloperoxidase, and also to investigate the molecular controls that lead to a cessation of their expression. 

The result of the recovery process is an enzyme contained in a solution that serves as the starting point for the formulation of the final product. The recovery process therefore needs to take the different formulation requirements into account. An enzyme concentrate to be used for a liquid enzyme formulation needs to have an enzyme concentration high enough to allow for dilution by formulation chemicals. Furthermore, the demand for physical and enzymatic stability of the liquid enzyme product typically requires that the recovery process reduces compounds (salts) that can precipitate or degrade the enzyme (e.g., proteases). Enzyme concentrates to be used for a dry formulation (granulate) need to fill the requirements on activity and dry matter content. A low activity to dry matter ratio will make it difficult to obtain sufficiently high enzyme concentration. 

Figure 4 Stabilized bromine antimicrobials are produced by eosinophils, a type of mammalian white blood cell. Bacteria are captured by phagocytosis and contained intracellularly within vesicles called phagosomes. Granules release cationic surfactants, lytic enzymes, and eosinophil peroxidase into the phagosome in a process known as degranulation. Eosinophil peroxidase, an enzyme that is structurally similar to the bromoperoxidases found in seaweed (Figure I), selectively catalyzes oxidation of bromide to hypobromite by reducing hydrogen peroxide to water. The hypobromite immediately reacts with nitrogenous stabilizers such as aminoethanesulfonic acid (taurine) to form more effective and less toxic antimicrobial agents.

The i-poly(3HB) depolymerase of R. rubrum is the only i-poly(3HB) depolymerase that has been purified [174]. The enzyme consists of one polypeptide of 30-32 kDa and has a pH and temperature optimum of pH 9 and 55 °C, respectively. A specific activity of 4 mmol released 3-hydroxybutyrate/min x mg protein was determined (at 45 °C). The purified enzyme was inactive with denatured poly(3HB) and had no lipase-, protease-, or esterase activity with p-nitro-phenyl fatty acid esters (2-8 carbon atoms). Native poly(3HO) granules were not hydrolyzed by i-poly(3HB) depolymerase, indicating a high substrate specificity similar to extracellular poly(3HB) depolymerases. Recently, the DNA sequence of the i-poly(3HB) depolymerase of R. eutropha was published (AB07612). Surprisingly, the DNA-deduced amino acid sequence (47.3 kDa) did not contain a lipase box fingerprint. A more detailed investigation of the structure and function of bacterial i-poly(HA) depolymerases will be necessary in future. 

Pancreatin is a pancreatic extract usually obtained from the pancrease of slaughterhouse animals. It contains a mixture of enzymes, principally amylase, protease and lipase, and, thus, exhibits a broad digestive capability. It is administered orally mainly for the treatment of pancreatic insufficiency caused by cystic fibrosis or pancreatitis. As it is sensitive to stomach acid, it must be administered in high doses or, more usually, as enteric-coated granules or capsules that may be taken directly or sprinkled upon the food prior to its ingestion. Individual digestive activities, such as papain, pepsin or bromelains (proteases), or a-amylase are sometimes used in place of pancreatin. 

Ordinarily, low concentrations of catecholamines are free in the cytosol, where they may be metabolized by enzymes including monoamine oxidase (MAO). Thus, conversion of tyrosine to l-DOPA and l-DOPA to dopamine occurs in the cytosol dopamine then is taken up into the storage vesicles. In norepinephrine-containing neurons, the final P-hydroxylation occurs within the vesicles. In the adrenal gland, norepinephrine is N-methylated by PNMT in the cytoplasm. Epinephrine is then transported back into chromaffin granules for storage. 

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