Homology of L-gulonolactone oxidase of species belonging to Mammalia, Aves, and Amphibia

Immunological cross-reactivity of L-gulonolactone oxidase of different species (rat, chicken, and bullfrog) was tested by the Ouchterlony technique. Antiserum directed against the enzyme from chicken kidney reacted with rat liver enzyme as well as with bullfrog kidney enzyme. This finding suggests that there is, at least partly, sequence homology among the enzyme from species belonging to the three classes, Mammalian, Aves, and Amphibia.     

Action of iodine on the tomato pectinesterase

Summary The organophosphates and carbamates did not inhibit the isolated tomato pectinesterase. Therefore this enzyme cannot be defined as serine-type esterase. The enzyme is inhibited by iodine and the inhibition (irreversible and non-competitive) is dependent on the degree of enzyme purification.     

Homology of L-gulonolactone oxidase of species belonging to Mammalia,Aves, and Amphibia

Summary Immunological cross-reactivity of L-gulonolactone oxidase of different species (rat, chicken, and bullfrog) was tested by the Ouchterlony technique. Antiserum directed against the enzyme from chicken kidney reacted with rat liver enzyme as well as with bullfrog kidney enzyme. This finding suggests that there is, at least partly, sequence homology among the enzymes from species belonging to the three classes, Mammalia, Aves, and Amphibia.     

Characterization of a soluble form of dipeptidyl peptidase IV from pig liver

Soluble dipeptidyl peptidase IV (EC 3.4.14.5) was purified from the 100,000 X g supernatant fraction of pig liver homogenate. The purified enzyme had the same properties as, and immunological identity with, the membrane-bound enzyme which was described previously. However, the purified enzyme had a pattern of molecular heterogeneity different from the membrane-bound enzyme; this was shown by isoelectric focusing. Carbohydrate analysis revealed that the soluble enzyme contained glucose, which is not found in the membrane-bound one, and less fucose, mannose, and sialic acid than the latter. From these results, we conclude that the soluble form of dipeptidyl peptidase IV in pig liver is closely related to the membrane-bound enzyme, but is not simply a proteolytically solubilized product of it.     

Characterization of a soluble form of dipeptidyl peptidase IV from pig liver

Summary Soluble dipeptidyl peptidase IV (EC 3.4.14.5) was purified from the 100,000×g supernatant fraction of pig liver homogenate. The purified enzyme had the same properties as, and immunological identity with, the membrane-bound enzyme which was described previously. However, the purified enzyme had a pattern of molecular heterogeneity different from the membrane-bound enzyme; this was shown by isoelectric focusing. Carbohydrate analysis revealed that the soluble enzyme contained glucose, which is not found in the membrane-bound one, and less fucose, mannose, and sialic acid than the latter. From these results, we conclude that the soluble form of dipeptidyl peptidase IV in pig liver is closley related to the membrane-bound enzyme, but is not simply a proteolytically solubilized product of it.We would like to thank Miss S. Fukushima for technical assistance.     

Cleavage of des-Arg9-bradykinin by angiotensin I-converting enzyme from pig kidney cortex

Fast and very slow hydrolyses of des-Arg9-bradykinin and angiotensin II by angiotensin I-converting enzyme were detected by high performance liquid chromatography. The Michaelis constants of the enzyme, Km values, for des-Arg9-bradykinin and bradykinin were found to be 0.24 mM and 4.4 microM, and the maximum velocities, Vmax values (mumol . min-1 . mg protein-1) for these compounds to be 3.24 and 0.34, respectively. The enzyme also hydrolyzed Z-Gly-Pro-Gly-Gly-Pro-Ala to a tripeptide that was identified as dansyl-Gly-Pro-Ala by TLC on polyamide. These observations show that the enzyme hydrolyzes the peptides at the bond before the prolyl residue in the penultimate position.     

Evidence for essential catalytic determinants for human erythrocyte pyrimidine 5′-nucleotidase

Human erythrocyte pyrimidine 5′-nucleotidase, PN-I, catalyzes the dephosphorylation of pyrimidine nucleoside monophosphates. The enzyme also possesses phosphotransferase activity, transferring phosphate groups between pyrimidine nucleoside monophosphates and various pyrimidine nucleosides. Deficiency of the enzyme activity is associated with a hemolytic anemia. PN-I cDNA has been expressed in Escherichia coli, yielding a fully active recombinant enzyme, which was purified to homogeneity and extensively characterized. Multiple sequence alignment of PN-I and homologues proteins revealed the existence of conserved regions, whose importance in catalysis was examined by performing experiments designed to intercept covalent intermediates as strongly suggested by our previous kinetic studies. Furthermore, a functional analysis of the enzyme was carried out through site-directed mutagenesis designed on the basis of the sequence of the identified conserved regions as well as mutations observed in PN-I-deficient patients.Received 25 March 2005; received after revision 3 May 2005; accepted 13 May 2005     

Partial purification and characterization of acid phosphatase from sporulated oocysts of Eimeria tenella

Acid phosphatase of Eimeria tenella oocysts (Peak II) was purified 77-fold with a recovery of 26% using protamine sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. This enzyme occurs in multiple forms as indicated by two peaks which can be separated by DEAE-cellulose chromatography and polyacrylamide gel electrophoresis. The partially purified enzyme has optimal activity at pH 4.5. With p-nitrophenyl phosphate the Km and Vmax values for (Peak II) were 25 mM and 1.57 mumol/min/mg protein, respectively. The enzyme (Peak II) is strongly inhibited by Hg++, Cu++, iodoacetamide, fluoride and molybdate. Tartrate and other divalent metal ions have no effect on enzyme activity. The partially purified Peak II phosphatase is not a glycoprotein as it is not absorbed on concanavalin-A Sepharose and its treatment with bacterial neuraminidase does not alter its elution profile through DEAE cellulose.     

On the distribution of plasma L-asparaginase

The guinea-pig, Cavia porcellus, is unusual in possessing plasma L-asparaginase, an enzyme with anti-tumor activity, 21 additional species have been examined as to the presence of this enzyme: the results confirm and extend its remarkably limited species distribution.     

Immunochemical studies on Rhodotorula gracilis D-amino acid oxidase.

Polyclonal antibodies were prepared from rabbit sera after immunization with holo- and apo-D-amino acid oxidase purified from R. gracilis. Both anti-holo- and anti-apoenzyme IgG fractions (as well as affinity-purified IgG) were highly specific: in blot-transfer analyses after SDS-PAGE only a 39 kDa band, corresponding to enzyme monomer, was recognized even in the partially purified yeast extract. No cross-reaction was detected with pig kidney D-amino acid oxidase. As a difference from the mammalian enzyme, yeast D-amino acid oxidase anti-holo- and anti-apoenzyme IgGs had different properties in inactivation and precipitation experiments, indicating the existence of different antigenicity sites related to the FAD-binding domain in the enzyme.     

Immunochemical studies onRhodotorula gracilis D-amino acid oxidase

Summary Polyclonal antibodies were prepared from rabbit sera after immunization with holo- and apo-D-amino acid oxidase purified fromR. gracilis. Both anti-holo- and anti-apoenzyme IgG fractions (as well as affinity-purified IgG) were highly specific: in blot-transfer analyses after SDS-PAGE only a 39 kDa band, corresponding to enzyme monomer, was recognized even in the partially purified yeast extract. No cross-reaction was detected with pig kidney D-amino acid oxidase. As a difference from the mammalian enzyme, yeast D-amino acid oxidase anti-holo- and anti-apoenzyme IgGs had different properties in inactivation and precipitation experiments, indicating the existence of different antigenicity sites related to the FAD-binding domain in the enzyme.     

Über Vorkommen von Kohlensäureanhydratase in der menschlichen Haut

Summary Carbonic anhydrase activity, as demonstrated histochemically, is present in human skin. Especially high enzyme activity was found in eccrine sweat glands. Probably there are relations between acide nature of sweat and enzyme activity. Full-length report see in Arch. Dermat.     

Affinity chromatography of glucose dehydrogenase

Porcine liver beta-D-glucose dehydrogenase, a multi-functional protein, has been purified to apparent homogeneity. The enzyme has been separated from the endoplasmic reticulum using Triton X-114 and further purified using NAD to release glucose dehydrogenase from a NADP-linked sepharose column. The purified enzyme is capable of producing both NADH and NADPH in vivo as indicated by kinetic studies.     

Purification and properties of ornithine aminotransferase from rat brain

Ornithine aminotransferase (E.C. 2.6.1.13) from rat brain was purified 100-fold by ammonium sulphate fractionation, DEAE cellulose chromatography, calcium phosphate gel and alumina C gamma gel. Pyridoxal phosphate was essential for maximum activity of the enzyme. The brain enzyme did not differ from liver and kidney enzymes in properties such as pH optimum, Km, substrate specificity and the inhibition by branched chain amino acids. Unlike rat liver enzyme, brain ornithine aminotransferase was able to catalyze the reaction between L-lysine and 2-oxoglutarate. Spermidine and spermine inhibited brain ornithine aminotransferase activity.     

Adenosine triphosphatase ofAspergillus nidulans: Stimulation by aminoacids

Summary Ca²⁺-dependent ATPase ofAspergillus nidulans was found to be stimulated by aminoacids in vitro. Both histidine and arginine stimulated the enzyme more effectively than the aromatic aminoacids. Supplementation of the growth medium with basic or aromatic aminoacids increased the enzyme activity in vivo 2–6-fold. The enhanced activity observed in these cultures in vivo was not mediated through the synthesis of new isoenzyme, as observed in proteinenriched cultures, but appeared to be through the activation of enzyme activity.     

Enzymatic N-acetylation of tryptamine by brain homogenates of Locusta migratoria before and after intoxication by chlordimeform or lindane (author's transl)]

Brain homogenates of Locusta migratoria are found to possess enzyme capable of catalyzing the N-acetylation of tryptamine. A main product of the enzymatic reaction is isolated and identified as N-acetyltryptamine by chromatography analyse. Both insecticides, chlordimeform and lindane, inhibit enzyme activity. A direct correlation between the degree of intoxication and acetylation of tryptamine is described.     

Alkaline phosphatase activity in normal and denervated skeletal muscle

Summary Changes in the specific activity of alkaline phosphatase in the normal and denervated skeletal muscle have been studied both histochemically as well as biochemically for a maximum period of 8 weeks of its postnatal development. In the normal muscle, a heterogenous population of fibres with respect to the enzyme distribution is observed. Relatively higher levels of enzyme in the denervated muscle and also the proliferation of extrafibrillar connective tissue in the diseased muscle show its specific association with the lytic processes.     

Enzymatic profile ofKluyvera species

Summary Kluyvera, a proposed genus formerly known as Enteric group 8, was found to have similar enzyme profiles among the present 3 groups.Kluyvera species group 3 showed the most heterogeneous enzyme reactions.To whom reprint requests should be addressed.     

Tissue-specific induction of intestinal glutathione S-transferases by alpha beta-unsaturated carbonyl compounds

Glutathione S-transferase activity in rat intestinal mucosa was increased by the injection of alpha beta-unsaturated carbonyl compounds such as phorone and diethylmaleate, but that in the liver and kidney was not. Since the administration of cycloheximide completely blocked the increase of the enzyme activity by phorone, the increase of the activity may be due to de novo synthesis rather than enzyme activation.