Biological Effects of Radiation: Mechanism and Measurement of Radiation, Applications in Biology, Photochemical Reactions, Effects of Radiant Energy on Organisms and Organic Products - Vol. 2

By Benjamin M. Duggar | Go to book overview

XXXVII
THE EFFECTS OF RADIATION ON ENZYMES

HAROLD A. SCHOMER Department of Botany, University of Wisconsin

The study of the relation of light to enzymes may be divided into two parts: (a) the use of light in the study of the structure of enzymes, mainly their absorption spectra, and (b) the possible effects of the absorbed radiation on the enzymes. Since the greatest progress in the purification of enzymes and in the perfection of physical apparatus in the field of radiation has been made in comparatively recent years, early work on irradiation of enzymes was necessarily rather crude and qualitative.

In 1879 Downes and Blunt (19) found that invertase ("zymase" from a fragment of yeast macerated in water and filtered) was inactivated by the full solar spectrum in the presence of oxygen. They concluded that the chief injury was due to the blue-violet portion, and that the inactivation was an oxidation reaction. Fermi and Pernossi (23) studied the effect of sunlight and temperature, together with various acids and salts, on various enzymes, the sources of which are not described. Pepsin and trypsin were found to be inactivated by long exposure (10 days) to sunlight. It was also reported that greater inactivation by light occurred at higher temperatures (54° to 56°C.), than at lower temperatures (37°C.). When exposed in the dry condition, these enzymes retained their activity over long periods of time (3 months). Similar results were obtained with ptyalin, diastase, and emulsin in the dry state, and in the presence of chloroform, ether, amyl alcohol, or benzol. Bacteria, exposed to sunlight, lost considerable of their proteolytic activity.

Green (30) made extensive studies on the action of sunlight and light from an electric are upon malt diastase solution, diastase in leaf tissue, and upon human saliva. Over a 24-hr. period, bright sunlight had no effect, while diffused light was found to increase slightly diastatic activity. After an exposure of 10 days the diastatic activity decreased 93 per cent. The various diastase solutions were also exposed to an electric are of 2000 candle power at a distance of 2 ft. for 10-, 12-, and 24-hr. periods. Exposures were made in open Petri dishes, the enzyme solutions being mixed to a gel with agar, then disposed in quartz vessels and in glass vessels. The entire spectrum was found to exert an attenuating influence on the diastatic activity; visible and infra-red rays (passed through glass)

-1151-

Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this page

Cited page

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited page

Bookmark this page
Biological Effects of Radiation: Mechanism and Measurement of Radiation, Applications in Biology, Photochemical Reactions, Effects of Radiant Energy on Organisms and Organic Products - Vol. 2
Table of contents

Table of contents

  • Title Page iii
  • Contents v
  • Xix Photoperiodism 677
  • Introduction 677
  • References 709
  • Xx Plant Growth in Continuous Illumination 715
  • References 725
  • Xxi the Effects of Light Intensity Upon Seed Plants 727
  • Introduction 727
  • References 757
  • Xxii Effects of Different Regions of the Visible Spectrum Upon Seed Plants 763
  • Introduction 763
  • Concluding Remarks 787
  • References 788
  • Xxiii Effect of the Visible Spectrum Upon the Germination of Seeds and Fruits 791
  • References 823
  • Xxiv the Effects of Visible and Ultra-Violet Radiation on the Histology of Plant Tissues 829
  • References 838
  • Xxv Some Infra-Red Effects on Green Plants 841
  • References 851
  • Xxvi the Effect of Ultra-Violet Radiation Upon Seed Plants 853
  • Introduction 853
  • Concluding Remarks 881
  • References 882
  • Xxvii the Effects of Radiation on Fungi 889
  • Introduction 889
  • References 910
  • Xxviii the Problem of Mitogenetic Rays 919
  • Introduction 919
  • Conclusions 944
  • References 946
  • Xxix Effects of X-Rays Upon Green Plants 961
  • Introduction 961
  • General Summary 980
  • References 983
  • Xxx the Effects of Radium Rays on Plants 987
  • References 1009
  • Xxxi the Light Factor in Photosynthesis 1015
  • References 1051
  • Xxxii the Influence of Radiation on Plant Respiration and Fermentation Charles J. Lyon 1059
  • Introduction 1059
  • Summary 1071
  • References 1072
  • Xxxiii Growth Movements in Relation to Radiation 1073
  • Xxxiv Chlorophyll and Chlorophyll Development in Relation to Radiation 1093
  • References 1104
  • Xxxv Radiation and Anthocyanin Pigments 1109
  • Introduction 1109
  • Conclusion 1116
  • References 1118
  • XXXVI - Effects of Radiation on Bacteria 1119
  • References 1141
  • Xxxvii the Effects of Radiation on Enzymes 1151
  • References 1160
  • Xxxviii Induced Chromosomal Aberrations in Animals 1167
  • Introduction 1167
  • References 1202
  • Xxxix Radiation and the Study of Mutation in Animals 1209
  • Introduction 1209
  • References 1252
  • Xl Induced Mutations in Plants 1263
  • Introduction 1263
  • References 1278
  • Xli Induced Chromosomal Alterations 1281
  • References 1293
  • Xlii Induced Chromosomal Alterations in Maize 1297
  • References 1308
  • Xliii Biological Aspects of the Quantum Theory of Radiation Absorptions in Tissues 1311
  • References 1326
  • Subject Index 1331
  • Alphabetical List of Contributors 1343
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this book
  • Bookmarks
  • Highlights & Notes
  • Citations
/ 1348

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.