{"title":"The chemical reactivity of the thiol group in the active centre of ficin","authors":"M.R. Hollaway, A.P. Mathias, B.R. Rabin","doi":"10.1016/0926-6569(64)90275-5","DOIUrl":"10.1016/0926-6569(64)90275-5","url":null,"abstract":"<div><p></p><ul><li><span>1.</span><span><p>1. The irreversible inhibition of ficin (EC 3.4.4.12) by chloroacetamide or iodoacetamide is due to the alkylation of the thiol group of one particular cysteine residue in the enzyme.</p></span></li><li><span>2.</span><span><p>2. The variation of the rate of alkylation of ficin with pH shows that the reactive thiol group of ficin behaves essenitally as a freely ionising roup, p<em>K</em><sub>a</sub>′ = 8.55 (25 °; <em>I</em>, 0.1). Hence it is concluded that this group is unlikely to exist in a hydrogen-bonded form in the free enzyme.</p></span></li><li><span>3.</span><span><p>3. The rates of reaction of ficin with chloroacetamide or iodacetamide were accelerated in the presence of substrates or products of catalytic activity without the stoichiometry of the overall reaction being affected. The rate of addition of the essential thiol of ficin to <em>N</em>-ethylmaleimide was unaffected by substrate or substrate analogues.</p></span></li><li><span>4.</span><span><p>4. The nucleophilicity of the essential thiol group of ficin in S<sub>N<sup>2</sup></sub> reactions was found to be greater than that of simple thiol compounds whereas in the addition reaction to <em>N</em>-ethylmaleimide the converse was found.</p></span></li><li><span>5.</span><span><p>5. A possible reason for the high nucleophilicyt of ficin in S<sub>N<sup>2</sup></sub> reactions and the acceleration caused by the presence of substrate or substrate analogues is given.</p></span></li></ul></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 111-124"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90275-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795481","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}
{"title":"Effect of monovalent cations on the adenosinetriphosphatase of sonicated erythrocyte membrane","authors":"Amir Askari, Joseph C. Fratantoni","doi":"10.1016/0926-6569(64)90277-9","DOIUrl":"10.1016/0926-6569(64)90277-9","url":null,"abstract":"<div><p></p><ul><li><span>1.</span><span><p>1. Human erythrocyte membrane contains a Mg<sup>2+</sup>-dependent adenosinetriphosphatase activity. The enhancement of this activity requires the simultaneous presence of Na<sup>+</sup> and K<sup>+</sup>. When the membranes were broken by ultrasonic vibrations, the adenosinetriphosphatase activity was enhanced with either Na<sup>+</sup> and K<sup>+</sup>, and in this case enhancement was no longer affected by ouabain.</p></span></li><li><span>2.</span><span><p>2. The effects of Mg<sup>2+</sup>, Ca<sup>2+</sup>, pH, and detergents on the various manifestations of the adenosinetriphosphatase activity, namely: (a) the Na<sup>+</sup>-plus-K<sup>+</sup>-dependent form, (b) the single-ion-dependent form, and (c) the ion-independent form, were studied. The results did not suggest the presence of more than one enzyme.</p></span></li><li><span>3.</span><span><p>3. Since the single-ion-dependent adenosinetriphosphatase activity was revealed merely by a physical change in the method of preparation (sonication), it is reasonable to suspect that it and the Na<sup>+</sup>-plus-K<sup>+</sup>-dependent activity are different manifestations of a single enzymic activity.</p></span></li></ul></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 132-141"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90277-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795483","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}
{"title":"The subcellular distribution of inorganic pyrophosphatase in pigeon pancreas","authors":"Gene D. Pynes, Ezzat S. Younathan","doi":"10.1016/0926-6569(64)90279-2","DOIUrl":"10.1016/0926-6569(64)90279-2","url":null,"abstract":"","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 150-151"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90279-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795485","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}
{"title":"Phosphorylation linked to oxidation of D(−) and L-lactate by respiring particles from yeast","authors":"Carlo Gregolin, Paola Scalella","doi":"10.1016/0926-6569(64)90284-6","DOIUrl":"10.1016/0926-6569(64)90284-6","url":null,"abstract":"","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 163-165"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90284-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795490","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}
{"title":"Studies on the repression of β-galactosidase in Escherichia coli","authors":"David J. Clark , Allen G. Marr","doi":"10.1016/0926-6569(64)90272-X","DOIUrl":"10.1016/0926-6569(64)90272-X","url":null,"abstract":"<div><p>The mechanism of catabolite repression has been tested in mutants of <em>Escherichia coli</em> and a mutant of <em>Aerobacter aerogenes</em>, JF-4, using the technique of nutrient limitation. Two distinct types of enzyme control have been identified: (1) a control which is antagonized by inducer and is called “inducer-specific repression”; and (2) a control which is independent of the concentration of inducer and is called “inducer-independent represseion”. A metho of analysis is employed which allows each of the two types of repression to be measured quantitavely. The restriction of catabolic activities leads to derepression while the restriction of anabolic activities leads to repression; however, the relative change in inducer-specific and inducer-independent repression are not the same. Carbon limitation leads to a preferential decrease in inducer-specific repression while nitrogen and sulfur limitation lead to a preferential increase in inducer-independent repression.</p></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 85-98"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90272-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23793360","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}
{"title":"Studies on bovine-liver alkaline phosphatase, purification, phosphate incorporation","authors":"Lorentz Engström","doi":"10.1016/0926-6569(64)90270-6","DOIUrl":"10.1016/0926-6569(64)90270-6","url":null,"abstract":"<div><p></p><ul><li><span>1.</span><span><p>1. A highly purified preparation of bovine-liver alkaline phosphatase (ortho-phosphoric monoester phosphohydrolase, EC 3.I.3.I) has been obtained from a liver homogenate treated with butanol. Acetone and ethanol fractionation have been used, followed by two consecutive chromatographies on TEAE-cellulose and one on Sephadex G-200.</p></span></li><li><span>2.</span><span><p>2. Labelled phosphorylserine has been isolated from acid hydrolysates of the purified enzyme, which had been incubated with radioactive orthophosphate and then inactivated by acid. Most probably, the phosphate was bound to a particular serine molecule at the active site of the enzyme. This supports the view that an intermediate phosphorylenzyme is formed during the action of alkaline phosphatase.</p></span></li></ul></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 71-78"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90270-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77550716","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}
{"title":"The hydrolysis of sucrose by intact and homogenized cells of rat small intestine. Influence of pH and substrate concentration","authors":"A. Dahlqvist, D.L. Thomson","doi":"10.1016/0926-6569(64)90273-1","DOIUrl":"10.1016/0926-6569(64)90273-1","url":null,"abstract":"<div><p>The intracellular locus of sucrose hydrolysis in rat small-intestinal mucosa has been studied <em>in vitro</em> using intestinal slices and homogenates of intestinal cells. The pH-activity curves for the invertase of the slices and homogenates were identical. The apparent <em>K</em><sub>m</sub> for the invertase activity of the slices was considerably higher than the <em>K</em><sub>m</sub> for the homogenates. The maximum velocity (<em>V</em>) for the slices and homogenates was nearly identical. Because of the difference in the apparent <em>K</em><sub>m</sub> values, it is postulated that a barrier exists between the apical surface of the cell and the site of hydrolysis of sucrose by invertase. Since the barrier slows the transport of sucrose to the enzyme in the intact cells but permits rapid pH equilibration between the enzyme locus and the fluid bathing and brush border, the barrier may be located superficially.</p></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 99-104"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90273-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23793361","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}
Glaci T. Zancan, Eduardo F. Recondo, Luis F. Leloir
{"title":"Enzymid dephosphorylation of adenosine diphosphate phosphoglyceric acid","authors":"Glaci T. Zancan, Eduardo F. Recondo, Luis F. Leloir","doi":"10.1016/0926-6569(64)90276-7","DOIUrl":"10.1016/0926-6569(64)90276-7","url":null,"abstract":"<div><p>An enzyme from muscle which acts on adenosine diphosphate phosphoglyceric acid and leads to the hydrolysis of the phosphate group at the 2-position of the glyceric acid moiety has been studied. The enzyme is strongly stimulated by inorgamoc pyrophosphate. This action is very specific. The enzyme also acts on 2,3-diphosphoglycerate.</p></div>","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 125-131"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90276-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795482","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}
{"title":"On the role of free radicals in tryptophan pyrrolase catalysis","authors":"P. Feigelson","doi":"10.1016/0926-6569(64)90293-7","DOIUrl":"10.1016/0926-6569(64)90293-7","url":null,"abstract":"","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 187-190"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90293-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23795499","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}
{"title":"Reversible dissociation of l-tartaric acid dehydrase into subunits","authors":"Ronald E. Hurlbert, William B. Jakoby","doi":"10.1016/0926-6569(64)90298-6","DOIUrl":"10.1016/0926-6569(64)90298-6","url":null,"abstract":"","PeriodicalId":100170,"journal":{"name":"Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects","volume":"92 1","pages":"Pages 202-204"},"PeriodicalIF":0.0,"publicationDate":"1964-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0926-6569(64)90298-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"23793352","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}