Enzyme of fish

Rehbein, H. 1979. Development of an enzymatic method to differentiate fresh and sea-frozen and thawed fish fillets J. Comparison of the applicability of some enzymes of fish muscle. Zeitschrift FUr Lebensmittel-Untersuchung undForschung A J69 263-265. 

Finally it should be mentioned that nutritional deficiencies are not always caused by incomplete diets. A surplus of one nutritional element in the diet may result in the deficiency of another one. The disturbing substance may interfere with the absorption of an indispensable factor (avidin-biotin) or destroy it (thiamin by enzyme of fish) or inhibit it by displacing it from its normal r61e (vitamin inhibitors) (162). Metabolic disorders of the mother or increased demands of the offspring (twins) may in the presence of an adequate diet result in states of nutritional deficiency. 

Fish proteia coaceatrates vary widely ia fuactioaal characteristics, ranging from those having high proteia coateat and low water solubiUty, to those having lower proteia coateats but improved water solubiUty. Attempts have beea made to improve fuactioaal properties of fish proteia by enzyme hydrolysis (141), or by modificatioa of the myofibrillar proteia by succiaylatioa (142). 

Some kinds of fish and Crustacea contain thiaminases. These enzymes cleave thiamin and thus inactivate the vitamin. Some plant phenols, e.g., chlorogenic acid, may possess antithiaminic properties, too, though their mechanism of action is so far not well understood. 

The mutagenic activity of the extracts was assayed using Salmonella typhimurium strain TA 1535, as described by McCann et al. (58). Ten ul of fish extract were spot-tested without addition of an S9-enzyme preparation (57). MNNG (20 ug/plate) was used as a positive control. 

Nicholls, D.M., K. Teichert-Kuliszewska, and G.R. Girgis. 1989. Effect of chronic mercuric chloride exposure on liver and muscle enzymes in fish. Comp. Biochem. Physiol. 94C 265-270. 

Egaas, E., J.U. Skaare, N.O. Svendsen, M. Sandvik, J.G. Falls, W.C. Dautennan, T.K. Collier, and J. Netland. 1993. A comparative study of effects of atrazine on xenobiotic metabolizing enzymes in fish and insect, and of the in vitro phase II atrazine metabolism in some fish, insects, mammals and one plant species. Comp. Biochem. Physiol. 106C 141-149. 

Gallbladder had 85% of radioactivity. Tb 1/2 values were 0.8 days for liver, 3.3 days for intestine, 3.5 days for gallbladder, and 8.2 days for liver Diets rich in fish oils produced marked increases in activities of P-450 cytochromes, 7-EROD, and other enzyme activities bass fed diets devoid of fish oil had lower microsomal enzyme activities... 

Varanasi, U. and D.J. Gmur. 1980. Metabolic activation and covalent binding of benzo[a]pyrene to deoxyribonucleic acid catalyzed by liver enzymes of marine fish. Biochem. Pharmacol. 29 753-762. 

The marine environment acts as a sink for a large proportion of polyaromatic hydrocarbons (PAH) and these compounds have become a major area of interest in aquatic toxicology. Mixed function oxidases (MFO) are a class of microsomal enzymes involved in oxidative transformation, the primary biochemical process in hydrocarbon detoxification as well as mutagen-carcinogen activation (1,2). The reactions carried out by these enzymes are mediated by multiple forms of cytochrome P-450 which controls the substrate specificity of the system (3). One class of MFO, the aromatic hydrocarbon hydroxylases (AHH), has received considerable attention in relation to their role in hydrocarbon hydroxylation. AHH are found in various species of fish (4) and although limited data is available it appears that these enzymes may be present in a variety of aquatic animals (5,6,7,8). 

Exposure of various invertebrate species to high concentrations of petroleum did not induce mixed function oxidase activity. Enzyme activity was stimulated, however, in a number of fish tissues by petroleum. Different permutations can be addressed as to the significance of basal or induced levels of mixed function oxidases and hydrocarbon toxicity. AHH may have a physiological role in enhancing hydrocarbon clearance but may also increase the mutagenic-carcinogenic potential of hydrocarbons. Both of these concepts have been demonstrated in studies with fish (29,30). Induced AHH levels may permit a more rapid oxidative transformation with concomitant "disappearance" of parent hydrocarbons, but potentially toxic metabolites could be retained in tissues for longer periods (31). It is likely that at the enzymic level the... 

Induction did not occur under our exposure conditions in fish exposed to water saturated with a variety of pure hydrocarbons. The compounds studied are commonly found in other pollutants besides petroleum. It is reasonable to speculate that enzyme induction may not be a common response of fish in the environment to various pollutant hydrocarbons which may be available in the water column for short periods. 

Zajicek, J.L. Tillitt, D.E. Huckins, J.N. Petty, J.D. Potts, M.E. Nardone, D.A. 1996, Application of Enzyme-Linked Immunosorbent Assay (ELISA) for Measurement of Polychlorinated Biphenyls (PCBs) from Hydrophobic Solutions Extracts of Fish and Dialysates of Semipermeable Membrane Devices (SPMDs). In Environmental Immunochemical Methods, ACS Symposium Series 646 American Chemical Society Washington, D.C. Chapter 26, pp 307-325. 

Metabolism of PAHs by the cytochrome P-450-dependent enzymes in fish is a classic deviation from EP theory. When PAH biotransformation product data are available (e.g., concentrations of PAH conjugates or other metabolites in bile). 

Not every fishing system works as well and preserves fish as long as the ones used in Iceland and Norway. Spoilage at sea is very common and contributes substantially to the loss of fishery resources. Several factors affect the keeping quality of fish held cai trawlers. One factor is the temperature of the water from which the catch is taken. Fish from hi temperature water needs less chilling to inhibit enzyme activity fish from very low temperature waters need very low temperature chilling to retard enzyme activity (13). 

Enzyme-Immunoassay. Fish tissue samples for testing were cut into uniform 3mm thick slices with parallel razor blades mounted on a handle. Four discs were then punched out from each slice with a stainless steel borer, 3-mm in diameter, and each disc was placed in a well of a 96-well polystyrene microtiter plate (Flow Laboratories, Inc., Hamden, CT). Samples were washed once with 0.2 ml Tris buffer. After the wash solution was aspirated, each sample was fixed in 0.2 ml of 0.3% H O -methanol fixative for 30 min. at room temperature. Samples were then transferred to clean wells and 0.2 ml of a 1 100 dilution of sheep-anti-ciguatoxin-horseradish peroxidase conjugate in Tris buffer was added to each well. The plate was then incubated at room temperature for 1 hr. The sheep-anti-cigua-toxin-horseradish peroxidase was removed by aspiration, and the tissues were immersed for 5 min. in 0.2 ml Tris buffer. Each sample was transferred to clean wells and incubated for 5 min. at room temperature with 0.2 ml of 4-chloro-l-naphthol substrate. The final steps involved removal of the tissue and addition of 0.015 ml of 3 M sodium hydroxide to stop the enzymatic reaction. Absorbance readings at 405 nm of each well were obtained in the Titertek Multi-skan (Flow Laboratories, Inc., Hamden, CT). 

The analysis of fish tissues for ciguatoxin by a newly developed enzyme-immunoassay procedure (26, 27) has been carried out in this study. Three areas of examinations have been attempted (1) the examination of clinically defined and documented and non-toxic consumed fish samples (2) the assessment of freshly caught fishes from the sites in the Leeward part of the island of Oahu where ciguatoxin is found and (3) competitive inhibition with suspension of purified ciguatoxin and closely related structurally similar polyether toxins. 

The comparison of clinically defined and documented toxic with non-toxic consumed fishes by EIA clearly demonstrated a statistically significant difference (p <0.001) between the two populations. This result is similar to that reported for the radioimmunoassay and enzyme-immunoassay procedures (21, 22, 26-28). The assessment of the EIA with each species of fish samples caught in the Hawaiian waters presented positive and borderline frequency values comparable to that reported earlier by Ito and Uchida (28) by the RIA, and more recently by Kimura et al. (27) by the EIA. 

Amine build-up in fish muscle usually results from decarboxylation of amino acids in the muscle by enzymes of bacterial origin. This review will present information on the activity of bacterial decarboxylases and the formation of amines in fish. Mechanisms of decarboxylase action and production of bacterial decarboxylases in fish muscle are discussed. Emphasis is placed upon studies dealing with formation of histidine decarboxylase and histamine. Histamine, because of its involvement in Scombroid food poisoning, has been extensively studied with regard to its formation in fish and fishery products. 

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