The Role of Two Complementary Fractions of Gramicidin S Synthesizing Enzyme System*

1968 ◽  
Vol 64 (2) ◽  
pp. 259-261 ◽  
Author(s):  
HAJIME ITOH ◽  
MICHIYUKI YAMADA ◽  
SHIRO TOMINO ◽  
KIYOSHI KURAHASHI
Keyword(s):  
Enzyme System ◽  
Gramicidin S

scholarly journals POPULATION GENETICS OF DROSOPHILA AMYLASE. IV. SELECTION IN LABORATORY POPULATIONS MAINTAINED ON DIFFERENT CARBOHYDRATES

Genetics ◽  
1983 ◽  
Vol 103 (4) ◽  
pp. 675-689
Author(s):  
Jeffrey R Powell ◽  
Marko Andjelković
Keyword(s):  
Structural Gene ◽  
Amylase Activity ◽  
Enzyme System ◽  
Specific Expression ◽  
Carbohydrate Source ◽  
Laboratory Populations ◽  
Consistent Change ◽  
Regulation Changes ◽  
Starch Medium

ABSTRACT Two polymorphic systems impinging on α-amylase in Drosophila pseudoobscura have been studied in laboratory populations maintained on medium in which the only carbohydrate source was starch (the substrate of amylase) and replicas maintained on medium in which the only carbohydrate source was maltose (the product of amylase). The two polymorphic systems were alleles at the structural gene (Amy) coding for the enzyme (allozymes) and variation in the tissue-specific expression along the adult midgut controlled by several genes. In the seven populations on maltose medium little consistent change was noted in either system. In the seven populations on starch medium, both polymorphisms exhibited selective changes. A midgut pattern of very limited expression of amylase rose in frequency in all starch populations, as did the frequency of the "fast" (1.00) Amy allele. The overall specific amylase activity did not differ between starch-adapted and maltose-adapted flies.—The results, along with previous studies, indicate that when a gene-enzyme system is specifically stressed in laboratory populations, allozymes often exhibit selective differences. Such results make the selectionist hypothesis at least tenable. Furthermore, the fact that both types of polymorphisms responded to selection indicates the role of structural gene vs. gene regulation changes in adaptive evolution is not an either/or question but one of relative roles and interactions.

scholarly journals Cytochemical methods for the localization of adenylate cyclase. A review and evaluation of the efficacy of the procedures.

1983 ◽  
Vol 31 (1) ◽  
pp. 85-93 ◽  
Author(s):  
L S Cutler
Keyword(s):  
Adenylate Cyclase ◽  
Cyclic Nucleotides ◽  
Cell Biology ◽  
Enzyme System ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cellular Functions ◽  
Cytochemical Localization ◽  
Biochemical Evaluation

The cytochemical procedures for localizing adenylate cyclase have been a source of controversy since their introduction. The importance of cyclic adenosine monophosphate (AMP), the product of adenylate cyclase's action on adenosine triphosphate (ATP), in cell biology is clear. Thus, the ability to localize this enzyme system reliably is an important tool in the study of various cellular functions. This report reviews the literature and presents a biochemical evaluation of the methods for localizing adenylate cyclase. The review and data presented serve to clarify many of the controversies surrounding this important cytochemical procedure. It is evident that although there are problems associated with localizing the enzyme, several valid procedures are currently available for the cytochemical localization of adenylate cyclase. In using these procedures, the effects of fixation and the capture agent on adenylate cyclase activity in the particular tissue being studied should be considered. Only repurified adenylyl imidodiphosphate [App(NH)p] should be used in the incubation medium. If care is taken, the use of these techniques can be of great value in the continued study of the role of cyclic nucleotides in cell biology.

Further studies on the role of phenylalanine in gramicidin S biosynthesis by Bacillus brevis

1984 ◽  
Vol 1 (2) ◽  
pp. 81-94 ◽  
Author(s):  
J.-H. David Wu ◽  
Linda Yang ◽  
Arnold L. Demain
Keyword(s):  
Bacillus Brevis ◽  
Gramicidin S

scholarly journals The breakdown and synthesis of starch by an enzyme system from pea seeds

1940 ◽  
Vol 128 (853) ◽  
pp. 421-450 ◽  
Keyword(s):  
Higher Plants ◽  
Enzyme System ◽  
Animal Tissues ◽  
Outstanding Achievement ◽  
Intermediary Role ◽  
Pea Seeds ◽  
Extensive Body ◽  
Phosphorylated Sugars ◽  
Derivatives Of

The gradual elucidation of the intermediary role of phosphorylated sugars in the breakdown of carbohydrate by the enzymes of yeast and certain animal tissues forms an outstanding achievement in the field of the biochemistry of carbohydrates. It is attractive to suppose that the rapid interconversions of carbohydrates which occur in the higher plants may depends also upon the formation of labile phosphorylated derivatives of sugars. It cannot be claimed, however, that this view is supported by any extensive body of facts. Since so far as the higher plants are concerned, only fragmentary observations have been recorded on the occurrence and nature of phosphorylated sugars; relatively little is known may be present to act upon such esters. Investigations to be described in this and subsequent communications are directed towards various aspects of this metabolic problem. In the present paper it is proposed to consider a system of enzymes extracted from mature pea seeds which illustrates one type of mechanism by which phosphoric ester are formed in vegetable tissues. Further, the study of this system has disclosed the mechanism by which starch is synthesized in the plant.

scholarly journals The presence and possible role of phosphopantothenic acid in gramicidin S synthetase

FEBS Letters ◽  
1970 ◽  
Vol 7 (3) ◽  
pp. 287-290 ◽  
Author(s):  
C.C. Gilhuus-Moe ◽  
T. Kristensen ◽  
J.E. Bredesen ◽  
T.-L. Zimmer ◽  
S.G. Laland
Keyword(s):  
Gramicidin S

Biochemistry and site-directed mutational analysis of Δ7-sterol-C5(6)-desaturase

2000 ◽  
Vol 28 (6) ◽  
pp. 799-803 ◽  
Author(s):  
A. Rahier ◽  
P. Benveniste ◽  
T. Husselstein ◽  
M. Taton
Keyword(s):  
Biochemical Characterization ◽  
Mutational Analysis ◽  
Enzyme System ◽  
Conserved Residues ◽  
Catalytic Role ◽  
Membrane Bound ◽  
Haem Iron ◽  
Oxygen Site

This report describes recent work on the process of desaturation at C5(6) of sterol precursors in plants. Biochemical characterization of the plant Δ7-sterol C5(6)-desaturase (5-DES) indicates that the enzyme system involved shows important similarities to the soluble and membrane-bound non-haem iron desaturases found in eukaryotes, including cyanide and hydrophobic chelators sensitivity, CO resistance and a requirement for exogenous reductant and molecular oxygen. Site-directed mutational analysis of highly conserved residues in 5-DES indicated that eight histidine residues from three histidine-rich motifs were essential for the catalysis, possibly by providing the ligands for a putative Fe centre. This mutational analysis also revealed the catalytic role of the functionally conserved Thr-114.

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