Where is DNase

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
joveryant
Garter
Garter
Posts: 6
Joined: Fri Oct 13, 2006 6:34 am

Where is DNase

Post by joveryant » Fri Oct 13, 2006 6:39 am

hi everyone, I have a littile question:

Since DNase degrades DNA into ATP......

We won't place DNA in RT for too long.

What confused me is "where is DNase come from?!"

User avatar
Dr.Stein
King Cobra
King Cobra
Posts: 3501
Joined: Thu Jul 07, 2005 7:58 am
Location: 55284 Yogyakarta, Indonesia
Contact:

Re: Where is DNase

Post by Dr.Stein » Sat Oct 14, 2006 3:49 am

joveryant wrote:Since DNase degrades DNA into ATP......

:shock: I don't think DNAse converts DNA into ATP... it is an enzyme to "open" the double-helix to facilitate transcription process :? This is not my major, I am blank :oops:
Image

joveryant
Garter
Garter
Posts: 6
Joined: Fri Oct 13, 2006 6:34 am

thanks

Post by joveryant » Sun Oct 15, 2006 11:05 pm

Hi Keef! thank you :lol:

User avatar
dipjyoti
Coral
Coral
Posts: 142
Joined: Thu Sep 21, 2006 7:04 am
Location: CALCUTTA;INDIA

Post by dipjyoti » Mon Oct 16, 2006 8:14 am

DNase I is a versatile enzyme that nonspecifically cleaves DNA to release 5'-phosphorylated di-, tri-, and oligonucleotide products (1). A powerful research tool for DNA manipulations, DNase I is used in a range of molecular biology applications. Some of its uses include:

degradation of contaminating DNA after RNA isolation,
"clean-up" of RNA prior to RT-PCR and after in vitro transcription,
identification of protein binding sequences on DNA (DNase I footprinting),
prevention of clumping when handling cultured cells, and
creation of a fragmented library of DNA sequences for in vitro recombination reactions.
While frequently used in the laboratory, the activity of DNase I is still a mystery to many researchers. Are the "units" of one source of DNase I the same as that of another? Are calcium and magnesium ions required for activity? Will DNase I degrade DNA in DNA:RNA hybrids? Can DNase I remove 100% of DNA contamination from RNA preparations? In this article we will try to answer some of the questions surrounding this commonly used enzyme.

Better Unit Definition

The specific activity of a given DNase I preparation reflects the potency of the enzyme per unit mass in degrading double-stranded DNA (dsDNA). Historically, this activity has been expressed in Kunitz units (2), where 1 Kunitz unit is the amount of DNase I added to 1 mg/ml salmon sperm DNA that causes an increase of 0.001 absorbance units per min when assayed in a 0.1 M NaOAc (pH 5.0) buffer. This buffer, however, is not representative of the conditions that are typical for DNase I digestions (see "Treating RNA Samples with DNase I" at right). Consequently, Ambion offers DNase I with a unit designation that better reflects how well the enzyme will degrade DNA under standard conditions. Updated procedures measure DNase I activity using real-time fluorescence assays which allows for fast, quantitative measurements.

For further info see http://www.sigmaaldrich.com/Area_of_Int ... ase_I.html

Thanx!
Dip Jyoti Chakraborty

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests