Guinea pigs, liver

Protein fraction from guinea pig liver Et,SnCl 488... 

A successful case study for asymmetric nitrogen oxidation was reported for a series of (hetero)aromatic tertiary amines. High diastereoselectivity was observed for the enzyme-mediated oxidation of S-(—)-nicotine by isolated CHMOAdneto to give the corresponding ds-N-oxide [215]. The stereoselectivity of this biooxidation was complementary to the product obtained by flavin M O (FM O) from human li ver (trows-selective [216]) as well as unspecific oxidations by FMOs from porcine and guinea pig liver. 

Lorand L, Parameswaran KN, Stenberg P, Tong YS, Velasco PT, Jonsson NA, Mikiver L, Moses P (1979) Specificity of guinea pig liver transglutaminase for amine substrates. Biochemistry 18 1756-1765... 

Moebius, F.F., Hanner, M., Knaus, H.G., Weber, F., Striessnig, J., and Glossmann, H. (1994) Purification and amino-terminal sequencing of the high affinity phenylalkylamine Ca2+ antagonist binding protein from guinea pig liver endoplasmic reticulum./. Biol. Chem. 269, 29314-29320. 

Both the enzymes were prepared by a special technique from the insoluble portion of guinea pig liver mitochondria, and they are quite specific with respect to the requirement of pyridine nucleotide (H9, Hll). However, dehydrogenases catalyzing reaction (25) with NAD as coenzyme have been reported (Mil, S13, T3), thus confirming the importance of the source of the enzyme and the purification procedure employed. 

Hll. Hollman, S., and Touster, O., The L-xylulose-xylitol enzyme and other polyol dehydrogenases of guinea pig liver mitochondria. ]. Biol. Chem. 225, 87-102 (1957). 

Panoutsopoulos GI, Beedham C. Kinetics and specificity of guinea pig liver aldehyde oxidase and bovine milk xanthine oxidase towards substituted benzaldehydes. Acta Biochim Pol 2004 51(3) 649-663. 

Alexander K, Baskin SI. 1987. Mechanistic studies of guinea-pig liver rhodanese [Abstract]. FedProc 46 954. 

The intracellular localization of carboxylesterases is predominantly microsomal, the esterases being localized in the endoplasmic reticulum [73] [79] [93], They are either free in the lumen or loosely bound to the inner aspect of the membrane. The carboxylesterases in liver mitochondria are essentially identical to those of the microsomal fraction. In contrast, carboxylesterases of liver lysosomes are different, their isoelectric point being in the acidic range. Carboxylesterase activity is also found in the cytosolic fraction of liver and kidney. It has been suggested that cytosolic carboxylesterases are mere contaminants of the microsomal enzymes, but there is evidence that soluble esterases do not necessarily originate from the endoplasmic reticulum [94], In guinea pig liver, a specific cytosolic esterase has been identified that is capable of hydrolyzing acetylsalicylate and that differs from the microsomal enzyme. Also, microsomal and cytosolic enzymes have different electrophoretic properties [77]. Cytosolic and microsomal esterases in rat small intestinal mucosa are clearly different enzymes, since they hydrolyze rac-oxazepam acetate with opposite enantioselectivity [95], Consequently, studies of hydrolysis in hepatocytes reflect more closely the in vivo hepatic hydrolysis than subcellular fractions, since cytosolic and microsomal esterases can act in parallel. 

The hydrolysis of the amide bond in chloramphenicol (4.26), which liberates dichloroacetic acid (4.27) and the primary amine (4.28), has been shown in bacteria, rodents, and humans [13-15]. In the microsomal fraction of guinea pig liver, moreover, the enzyme responsible for hydrolysis has been identified as one of the B-type carboxylesterase isoenzymes [16]. 

K. N. White, D. B. Hope, Partial Purification and Characterization of a Microsomal Carboxylesterase Specific for Sabcylate Esters from Guinea-Pig Liver , Biochim. Bio-phys. Acta 1984, 785, 138-147. 

J. H. Sherry, J. P. O Donnell, H. D. Colby, Conversion of Spironolactone to an Active Metabolite in Target Tissues Formation of 7a-Thiospironolactone by Microsomal Preparations from Guinea Pig Liver, Adrenals, Kidneys and Testes , Life Sci. 1981, 29, 2727-2736. 

Fll. Flodgaard, H. J., and Brodersen, R., Bilirubin glucuronide formation in developing guinea pig liver. Scand. J. Clin. Lab. Invest. 19, 149-155 (1967). 

Tugwood, J.D., Holden, P.R., James, N.H., Prince, R.A. Roberts, R.A. (1998) A peroxisome proliferator-activated receptor-alpha (PPARa) cDNA cloned from guinea-pig liver encodes a protein with similar properties to the mouse PPARa implications for species differences in responses to peroxisome proliferators. Arch. Toxicol., 72, 169-177 Turner, J.H., Petricciani, J.C., Crouch, M.L. Wenger, S. (1974) An evaluation of the effects of diethylhexyl phthalate (DEHP) on mitotically capable cells in blood packs. Transfusion, 14, 560-566... 

Price et al. (1996) compared the toxicity of 0.5, 1 and 2 mmol/L coumarin in 24 h cultured precision-cut male Sprague-Dawley rat, Dunkin-Hartley guinea-pig, cyno-molgus monkey and human liver slices. Coumarin toxicity, based on liver protein synthesis and potassium content, was concentration-dependent in rat and guinea-pig liver, whereas monkey and human liver were relatively resistant. 

We also studied various series of MAO inhibitors U) and formulated Eq. 7 and 8 for the data of substituted benzylhydrazdnes (2) and a-methyltryptamines (J), respectively, against MAO prepared from guinea pig liver mitochondria. 

UDP-GlcUA By oxidation of UDP-Glc with UDP-Glc dehydrogenase from bovine liver or guinea pig liver... 

Webber K. O. and Hajra A. K. (1993). Purification of dihydroxyacetone phosphate acyltransferase from guinea pig liver peroxisomes. Arch. Biochem. Biophys. 300 88-97. 

Glucuronides were produced continuously in an enzyme membrane reactor from aglycones and /3-D-uridine diphosphoglucuronic acid (UDPGA) in the presence of a guinea-pig liver preparation of /3-glucuronidase for between 24 and 118 h (Pfaar, 1999). 

Blood and various organs of humans and other animals contain esterases capable of acetylsalicylic acid hydrolysis. A comparative study has shown that the liver is the most active tissue in all animal species studied except for the guinea pig, in which the kidney is more than twice as active as the liver. Human liver is least active the enzyme in guinea pig liver is the most active. The relatively low toxicity of some of the new synthetic pyrethroid insecticides appears to be related to the ability of mammals to hydrolyze their carboxyester linkages. Thus mouse liver microsomes catalyzing (+)-/runs-resin e 111ri n hydrolysis are more than 30-fold more active than insect microsomal preparations. The relative rates of hydrolysis of this substrate in enzyme preparations from various species are mouse > > milkweed bug > > cockroach > > cabbage looper > housefly. 

It has now been established that in common with many other glu-curonides, bilirubin glucuronide can be synthesized in the adult rat, rabbit, mouse, and guinea pig liver by the enzymatic transfer of glucuronic acid from uridine diphosphate glucuronic acid to an acceptor substance, namely, bilirubin (Fig. 3) (B17, G5, L3, L5, S8). The transferring enzyme (glucuronyl transferase) has been shown by Schmid et al. 

Rat liver homogenate Guinea pig liver homogenate Dog liver homogenate Cat liver homogenate Polystictus versicolor Piricularia oryzae... 

The same phenomenon was observed for mitraciliatine (10) and the closed ring E alkaloids 14-19, where the percentage metabolism by O-demethylation estimated by formaldehyde production ( 1%) was much less than the degree of total metabolism (25-69%). Nevertheless, both hirsutine and mitraciliatine gave detectable amounts of a compound assumed by TLC analysis to be an 0-(17)-demethyl metabolite, whereas such was not the case with 14-19. Hirsutine and mitraciliatine were also metabolized (to unidentified products) by both rat and guinea pig liver microsomes, which did not metabolize alkaloids 4-6, 9, and 11-13. 

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