Canadian journal of biochemistry最新文献_第6页

A microassay for UDP-N-acetylglucosamine pyrophosphorylase. udp - n -乙酰氨基葡萄糖焦磷酸化酶的微量测定。

Canadian journal of biochemistry Pub Date : 1982-07-01 DOI: 10.1139/o82-088

P K Gopal, P A Sullivan, M G Shepherd

引用次数: 1

The biosynthesis of triterpenoid carotenoids in Streptococcus faecium UNH 564P. 粪链球菌UNH 564P中三萜类胡萝卜素的生物合成。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-084

B H Davies, R F Taylor

引用次数: 10

Sulphide as an inhibitor and electron donor for the cytochrome c oxidase system. 硫化物作为细胞色素c氧化酶系统的抑制剂和电子供体。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-076

P Nicholls, J K Kim

{"title":"Sulphide as an inhibitor and electron donor for the cytochrome c oxidase system.","authors":"P Nicholls, J K Kim","doi":"10.1139/o82-076","DOIUrl":"https://doi.org/10.1139/o82-076","url":null,"abstract":"Anomalies both kinetic and equilibrium in nature are described for the inhibition of cytochrome c oxidase activity by sulphide in the isolated enzyme and in submitochondrial particles. These anomalies are related to the involvement of more than 1 mol of sulphide in the blockage of one cytochrome aa3 centre. Sulphide reduces resting cytochrome a3, a reaction that results in oxygen uptake and the loss of a sulphide molecule. Sulphide can also reduce cytochromes c and a; in the former case, a part of the one-equivalent oxidation product, presumed to be the SH radical, reacts with oxygen. Such oxygen uptake is also seen under aerobic conditions when ferricyanide reacts with sulphide. Three phases are identified in the inhibitory interaction of sulphide with the cytochrome c oxidase enzyme itself: an initial rapid reaction involving sulphide oxidation, oxygen uptake, and conversion of cytochrome aa3 into the low-spin \"oxyferri\" form; a subsequent step in which sulphide reduces cytochrome a; and the final inhibitory step in which a third molecule of sulphide binds the a3 iron centre in the cytochrome a2+ a3 3+ (oxy) species to give cytochrome a2+ a3 3+ H2S. the initial events parallel some of the events in the interaction of the cytochrome c-cytochrome aa3 system with monothiols; the final inhibitory event resembles that with cyanide.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"613-23"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-076","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17349851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 186

A topoisomerase from chicken erythrocyte nuclei which does not assemble nucleosome core particles in vitro. 鸡红细胞核不聚合核小体核心颗粒的拓扑异构酶。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-080

M J Ellison, D E Pulleyblank

{"title":"A topoisomerase from chicken erythrocyte nuclei which does not assemble nucleosome core particles in vitro.","authors":"M J Ellison, D E Pulleyblank","doi":"10.1139/o82-080","DOIUrl":"https://doi.org/10.1139/o82-080","url":null,"abstract":"We have examined the ability of a topoisomerase purified from chicken erythrocyte nuclei to mediate nucleosome core assembly in vitro at physiological ionic strength (0.15 M NaCl). Although we have detected limited amounts of spontaneously assembled nucleosome cores at this salt concentration, the addition of this topoisomerase does not increase the amount of assembly observed. Nucleosome assembly was assayed by quantitating the amount of core particle length DNA accumulated with time upon the nuclease digestion of histone-DNA complexes. In addition, the amount of negative supercoils introduced into relaxed closed circular DNA upon nucleosome core particle assembly was determined. Correctly assembled complexes do not protect more DNA from nuclease digestion than random histone-DNA complexes but shift the heterogeneous size distribution of protected fragments to a more homogeneous distribution centred around 145 base pairs. Under our conditions of nucleosome assembly, a second histone-DNA complex which is distinct from the nucleosome core can be detected under physiological ionic strength conditions. This particle does not form in high salt assembly experiments. Similarly, the assembly of this particle is unaffected by the presence or absence of topoisomerase.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"651-8"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-080","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17350460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Resolution of diacylglycerol moieties of natural glycerophospholipids by gas-liquid chromatography on polar capillary columns. 极性毛细管色谱柱气液相色谱法解析天然甘油磷脂的二酰甘油分子。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-079

J J Myher, A Kuksis

{"title":"Resolution of diacylglycerol moieties of natural glycerophospholipids by gas-liquid chromatography on polar capillary columns.","authors":"J J Myher, A Kuksis","doi":"10.1139/o82-079","DOIUrl":"10.1139/o82-079","url":null,"abstract":"A rapid and practical method has been developed for the gas-liquid chromatographic determination of the sn-1,2-diacylglycerol moieties of natural glycerophospholipids using polar wall-coated open tubular columns. The method gives complete resolution and quantitative estimates for all species according to molecular weight and degree of unsaturation, including stearoyl docosahexaenoylglycerol and related polyunsaturates. For this purpose the sn-1,2-diacylglycerols are obtained from the glycerophospholipids by hydrolysis with phospholipase C and are converted into the trimethylsilyl or tertiary-butyldimethylsilyl ethers. The silyl ethers are separated by gas-liquid chromatography on the capillary glass columns coated with a polar cyanopropylsiloxane polymer, in the temperature range 175-250 degrees C, using hydrogen as the carrier gas. Practical applications of the method are illustrated by analyses of the sn-1,2-diacylglycerol moieties of the phosphatidylcholines of soybean phosphatides, egg yolk, and rat liver. The method of analysis is applicable to other classes of glycerophospholipids and the total time requirements for the analysis of any one phospholipid class are comparable to those for a fatty acid analysis.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"638-50"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-079","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17937978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 81

The inhibition of beta-galactosidase (Escherichia coli) by amino sugars and amino alcohols. 氨基糖和氨基醇对-半乳糖苷酶(大肠杆菌)的抑制作用。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-075

R E Huber, M T Gaunt

{"title":"The inhibition of beta-galactosidase (Escherichia coli) by amino sugars and amino alcohols.","authors":"R E Huber, M T Gaunt","doi":"10.1139/o82-075","DOIUrl":"https://doi.org/10.1139/o82-075","url":null,"abstract":"Kinetically determined competitive inhibitor constants, which were estimates of the binding capacity of inhibitors interacting with the free enzyme form of beta-galactosidase (Escherichia coli), showed that amino sugars and alcohols inhibited the enzyme much more than did their respective parent sugars and alcohols. In most cases the inhibition was 10-30 times greater, but the inhibition by 1-aminogalactopyranose was about 300 times greater than that of galactopyranose. When the amino groups were acetylated the inhibitory advantage was completely eliminated and partial neutralization of the amino group of an inhibitor by the presence of a group with a negative charge on the same inhibitor decrease the inhibitory advantage. Studies of binding to the galactosyl form of the enzyme (rather than to the free form) indicated that the binding at the \"glucose\" site was increased only slightly by the presence of the amino group. Overall, the findings suggested that beta-galactosidase has a negative charge near the anomeric carbon binding position of the \"galactose\" site. Since negative charges are unlikely to be of any importance in binding the normally neutral beta-galactosidase substrates, this charge may be important in stabilizing a positively charged reaction analogous to an oxonium-carbonium ion intermediate.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"608-12"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-075","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17863496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 18

A cell-free system for Streptococcus faecium for studies on the biosynthesis of triterpenoid carotenoids. 用于研究三萜类胡萝卜素生物合成的粪链球菌无细胞系统。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-083

R F Taylor, B H Davies

引用次数: 13

The structural heterogeneity of the carbohydrate moiety of desialylated human transferrin. 脱氮人转铁蛋白碳水化合物部分的结构异质性。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-077

L März, M W Hatton, L R Berry, E Regoeczi

{"title":"The structural heterogeneity of the carbohydrate moiety of desialylated human transferrin.","authors":"L März, M W Hatton, L R Berry, E Regoeczi","doi":"10.1139/o82-077","DOIUrl":"https://doi.org/10.1139/o82-077","url":null,"abstract":"Human transferrin consists of a single chain polypeptide which supports two N-glycosidically linked glycans at sequons a and b. Glycopeptides were released from human transferrin by proteolytic digestion, desialylated by mild acid hydrolysis, and then isolated by chromatographic methods. The structures of the glycans located on each sequon were determined by a combination of analytical techniques including Smith degradation, permethylation, and enzymic degradation. Approximately 79% of the total glycan from sequon a was of the biantennary type as previously described by Dorland and his colleagues (FEBS Lett. 77, 15-20 (1977)). The remaining 21% consisted of a mixture of triantennary and tetraantennary glycans, each amounting to approximately 10% of the total glycan for this sequon. The triantennary structure resembled that described for the N-glycosidic triantennary glycans of bovine fetuin by Nilsson and his colleagues (J. Biol. Chem. 254, 4545-4553 (1979)). Of the tetraantennary glycan, approximately half of the structures were incomplete, i.e., one antenna terminated by N-acetylglucosamine. On sequon b, 81% of the glycan was biantennary, identical to those biantennary glycans of sequon a, and the reminder was triantennary, also of the fetuin type. The glycan structures and their locations on the polypeptide are related to the known subpopulations of human transferrin.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"624-30"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18131373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 80

Reversible cryogenic alteration of the ultraviolet absorption spectra of the olefinic bonds in lipid membranes. 脂质膜中烯烃键紫外吸收光谱的可逆低温改变。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-073

I M Campbell, A B Pawagi

{"title":"Reversible cryogenic alteration of the ultraviolet absorption spectra of the olefinic bonds in lipid membranes.","authors":"I M Campbell, A B Pawagi","doi":"10.1139/o82-073","DOIUrl":"https://doi.org/10.1139/o82-073","url":null,"abstract":"In earlier studies it was found that the association of basic polypeptides with lipid vesicles drastically altered ultraviolet absorption by the olefinic bonds of the lipid. Such an effect suggested that the polypeptide was increasing the polarity of the chromophore environment by either direct interaction with the acyl chains or by inducing their hydration. It is reported here that freeze-thaw cycling, which was expected to allow hydration of the olefinic-bond region of the membranes, caused the same spectral alteration as vesicle interaction with basic polypeptides. When these vesicles were subsequently placed under conditions that would be expected to accelerate the escape of water entrapped within the membranes (i.e., by placing them under vacuum or adding sucrose to establish a high osmotic gradient to their exterior), the absorption spectrum was rapidly restored to that for olefinic bonds in a nonpolar environment. Since placing the polylysine- dioleoylphosphatidylcholine (DOPC) vesicle interaction product under the same conditions restored the spectral intensity, at 190 nm, to between 80 and 85% of that for the lipid in a nonpolar environment, it seems that a major effect of polylysine on DOPC membranes may be though induction of hydration of their interior.","PeriodicalId":9508,"journal":{"name":"Canadian journal of biochemistry","volume":"60 6","pages":"593-8"},"PeriodicalIF":0.0,"publicationDate":"1982-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1139/o82-073","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18131372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Inhibition of cathepsin L and B by haptoglobin, the haptoglobin-hemoglobin complex, and asialohaptoglobin. "In vitro" studies in the rat. 结合珠蛋白、结合珠蛋白-血红蛋白复合物和asialohaptoglobin对组织蛋白酶L和B的抑制作用。在大鼠身上进行的“体外”研究。

Canadian journal of biochemistry Pub Date : 1982-06-01 DOI: 10.1139/o82-078

M Pagano, M A Nicola, R Engler

引用次数: 14