Date of Publication

12-16-1992

Document Type

Master's Thesis

Degree Name

Master of Science in Chemistry

Subject Categories

Analytical Chemistry | Physical Chemistry

College

College of Science

Department/Unit

Chemistry

Thesis Adviser

Mi-Soon Lee

Defense Panel Chair

Anamy Paano

Defense Panel Member

Consolacion Ragasa
Christine Ngo

Abstract/Summary

In this work, the complexation reactions of Pb(II) with Herring sperm DNA were studied. The DNA solution prepared was tested for hyperchromicity and then, Pb(II) ions were added to form 0.0, 0.33, 0.5, 1.0, 1.5, and 2.0 Pb(11)/DNA mole ratio solutions. Changes in UV-Vis heating and reheating absorbance spectra (at 258 to 261 nm) of these solutions indicate the following:i. at low concentration (0.0 to 0.33), Pb(II) binds primarily to the phosphate backbone thereby stabilizing the DNA molecule and increasing its melting point.ii. at higher concentrations (0.50 to 2.0) however, Ph(II) also binds to the nucleic acid group. This gives an overall effect of destabilizing the DNA molecule and decreasing its melting point.iii. The binding of Pb(II) to the nucleic acids in the DNA holds the two strands of the double helix molecule in proximity upon heat denaturation. This makes the rewinding of the DNA molecule after cooling possible. At relatively high Pb(II) concentration [1.0 Pb(II)/DNA mole ratio and above] however, Pb(II) becomes too tightly bound to the DNA molecule and NaCl has to be added [to precipitate out the Pb(II)] for the rewinding process to occur.

Abstract Format

html

Language

English

Format

Print

Accession Number

TG02148

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

39 leaves

Keywords

Lead—Physiological effect; Pacific herring—Spermatozoa; DNA; Metal ions; Ultraviolet spectroscopy

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