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1979 (1)
1976 (1)
1Author    K. Irumakki, N. ShivaramRequires cookie*
 Title    Purification and Properties of Potato Phosphorylase Isozymes  
 Abstract    Two multiple forms of a-glucan phosphorylase which migrate about half way in polyacryl-amide-gel electrophoresis (named "slow" and "fast" isozyme), were isolated by combined chromato­ graphy and preparative electrophoresis after freezing the tissue from freshly harvested and from sprouting potato tubers respectively. Depending on the primer used for the synthesis reaction their pH optimum varied between 5.2 and 6.0 and the optimum temperature was 30 and 35 °C. The isoelectric point for the slow isozyme was at pH 5 .0 + 0.1 and for the fast isozyme, pH 5 .5 + 0.1, the molecular weights were 209 000 + 10 000 and 165 000 + 5000 and for their subunits 104 000 + 4000 and 40 000 + 2000 respectively. Both isozymes were inhibited by Hg2+, Ag+ and p-chloromercuro-benzoate (p-CMB). Fe2+ ions inhibited them partially. Mg2+, Mn2+ and sulfhydryl compounds acti­ vated both. K m values for the slow and fast isozymes with glucose-l-phosphate in presence of soluble starch was 6.7 and 8.0 mM, of amylose 14.3 and 20.0 mM and of glycogen 22.2 and 40.0 mM respectively. The affinity of the primer for the slow and the fast isozymes were as follows: soluble starch 0.5 and 1.0 mM, amylose 2.6 and 3.8 mM, glycogen 6.2 and 7.7 mM respectively. K m values of phos-phorolysis with soluble starch was 0.8 and 0.5 mM, with amylose was 3.1 and 1.1 mM, and with glycogen was 6.5 and 1.3 mM respectively. As substrate and primer the soluble starch was superior and the glycogen was inferior. Amylose was in between. Kinetic parameters suggested the existence of a-glucan phosphorylase isozymes with different specificities: the slow one being more active in the direction of starch synthesis and the fast iso­ zyme degrading faster the polyglucans. These observations suggest that the polyglucan synthesis and degradation in potato tubers may be regulated by the change in the proportion of slow and fast isozymes. ' 
  Reference    (Z. Naturforsch. 31c, 424 [1976]; received April 5 1976) 
  Published    1976 
  Keywords    Potato, Phosphorylase, Isozymes, Purification, Properties 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0424.pdf 
 Identifier    ZNC-1976-31c-0424 
 Volume    31 
2Author    H. Großmann, M. W. Einert, M. LiefländerRequires cookie*
 Title    Acetylcholinesterase aus dem Gift von Bungarus multicinctus. Reinigung und Eigenschaften The Acetylcholinesterase of Bungarus multicinctus Venom. Purification and Properties  
 Abstract    Acetylcholinesterase from Banded krait (Bungarus m ulticinctus) venom has been purified by CM -Sephadex chrom atography and affinity chromatography to a specific activity of 4290 U/mg. The purified enzyme is a glycoprotein. It is free of electrophoretically detectable contam inating proteins. A m olecular weight of 140 000 + 5 000 has been determ ined by gradient gel electro­ phoresis for the native enzyme. It is split into two equal-sized subunits (Mr 70 000 + 2 000) by SDS treatm ent. The N -term inal amino acid analysis gave glycine and serine. The purified acetyl­ cholinesterase can be resolved by disc gel electrophoresis into four and by isoelectric focusing into six isozymes. The p i value of the m ain isozyme has been found to be 5.98 + 0.05. 
  Reference    Z. Naturforsch. 34c, 27 (1979); eingegangen am 2. November 1978 
  Published    1979 
  Keywords    Acetylcholinesterase, Snake Venom, B ungarus m ulticinctus, Affinity Chromatography, Isozymes 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0027.pdf 
 Identifier    ZNC-1979-34c-0027 
 Volume    34