摘要:

AbstractChanges in amylose percentage and the activities of starch‐synthesizing enzymes were followed in cultures of Polytoma uvella over a 6‐day period. Phosphorylase, ADPG‐glucosyltransferase, amylose content, ADPG and UDPG concentrations reached a peak in 96 hrs. old cultures. At this stage the cells of shaken cultures contained much higher enzyme activities and much more starch than those of stagnant cultures. After 96 hrs. phosphorylase and transferase activities declined sharply, amylose percentage decreased from 13.5 % to 6 %, but starch production continued, be it at a lower rate. Since Q‐enzyme activity increased during this period, it is suggested that the decrease in amylose percentage was due to preponderant production of amylopectin. A high correlation existed between amylose percentage and starchbound transferase. Experiments were initiated to bring about differential inactivation of phosphorylase and ADPG‐glucosyl‐transferase by growing cultures at higher t

ISSN:0038-9056    

DOI:10.1002/star.19700221002

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractSynthetic glycogen with long external chain‐lengths has been prepared from glycogen and glucose‐1‐phosphate by the action of potato phosphorylase. Samples having external chains of average lengths of 9.7, 12.1, and 37.8 glucose units (original glycogen = 7.5 glucose units) have been prepared. The iodine‐binding characteristics, the behaviour on β‐amylolysis, and the dependence of sedimentation coefficient on concentration have been investigated. Results are consistent with the concept that the synthetic samples have a few exceedingly long external chains with the remainder the same length as in native glycogen. The significance of these results is

ISSN:0038-9056    

DOI:10.1002/star.19700221003

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe phosphorus of glucose‐6‐phosphate residue in starch (P(G6P)) was estimated specifically by means of glucose‐6‐phosphate dehydrogenase (E.C.1.1.1.49) after acid hydrolysis. Sixty to 70 % of total phosphorus in potato starch was found to be P(G6P)). It was shown that the rest of phosphorus (Px) was incorporated as glucose‐2‐phosphate and/or glucose‐3‐phosphate, since it was determined as glucose by periodate oxidation, borohydride reduction, acid hydrolysis and treatment with alkaline phosphatase. The Px was more labile to acid and heat than P(G6P) and decomposed yielding inorganic phosphate.The phospholigosacharide (D. P.3.6), which was prepared by the limit hydrolysis of potato starch with glucoamylase of Rh. delemar (α‐1,4‐Glucan glucohydrolase E.C.3.2.1.3) was fractionated by gel‐filtration through Sephadex G‐25 into fractions with D.P. 2 to 7. Each fraction contained a mole of phosphorus per mole of the saccharide. The P(G6P) and the Px were enriched in the low and the highD.P

ISSN:0038-9056    

DOI:10.1002/star.19700221004

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

The Specific Rotation of Sorbitol and of the Sorbitol Molybdate Complex.1The specific rotation of the hexite at 365, 405, 436, 546 and 578 nm has been determined in solutions of different concentration with a commercial sorbitol preparation as well as with a self‐produced sorbitol. Contents of both preparations had been determined enzymatically and by means of periodate. The specific rotation [α]Dwas obtained mathematically from these data as well as by graphic extrapolation.2Conditions, under which the sorbitol molybdate complex shows its maximum of specific rotation were defined by systematic experiments at varying sorbitol, molybdate and hydrogen‐ion concentration.3)From these results a diagram was set up, which shows the molybdate and acid doses in order to determine sorbitol polarimetrically in the widest possible range.4)The specific rotation of the sorbitol molybdate complex was determined at the same wavelengths as that of the sorbitol. It was also mathematically and graphically extrapolated for

ISSN:0038-9056    

DOI:10.1002/star.19700221005

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

摘要:

AbstractThe physical and chemical properties of starch and glycogen can be explained on the basis that glycogen is converted into amylose and amylopectin by a debranching enzyme (isoamylase) which removes the external α‐1,6‐linked branches of the glycogen. This precursor glycogen exists in all corn endosperm examined: ae high amylose, normal dent, waxy, and sweet corn. Analyses of amylopectins show that they behave as statistical condensation polymers (the model‐V of Erlander and French) which have been debranched. Further support for the mechanism is given by the fact that the chain length and degree of branching of the interior part of all amylopectins is essentially the same as that of its precursor glycogen. Any mechanism for starch synthesis must, however, consider the complexing of enzymes because both amylopectin and glycogen behave as if they were strongly complexed to proteins. Thus proteases can destroy these complexes and viscosity differences of various barley geneotype starches can be correlated to protein content. Acid hydrolysis studies on corn amylopectins suggest that the type of protein complexed with amylopectin changes with both endosperm maturity and corn variety. Amylose synthesis from debranched chains can be correlated with the ability of chromosomes to regulate when and in what sequence an enzyme is synthesized. The proposed model for desoxyribonucleic acid (DNA) – which is a hollow cylinder with the bases on the outside – can explain how these regulators (genetic repressors and inducers) can function. „Proofs”︁ for the Watson‐Crick model such as X‐ray analyses, hypochromism, and molecular dimensions are s

ISSN:0038-9056    

DOI:10.1002/star.19700221006

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700221007

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700221008

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700221009

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700221012

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY

ISSN:0038-9056    

DOI:10.1002/star.19700221014

出版商:WILEY‐VCH Verlag GmbH    

年代:1970

数据来源: WILEY