Specificity and correlation of Worthington deoxyribonuclease I

Deoxyribonuclease Ⅰ It is an endonuclease ,zui Zaoyou M．Kunitz The result of crystallization . The existence of ions has an obvious effect on the cutting mode . In the process of continuous research and development , It is also used as a research material .

Deoxyribonuclease Ⅰ It is the most representative endonuclease . The first is the M．Kunitz Isolated from the pancreas , Also known as pancreatic deoxyribonuclease or DNaseⅠ, EC3．1．21．1. The molecular weight is about 3.1 ten thousand , Isoelectric point pH4.7, Most suitable PH 7 near , need Mg2  and Mn2 . Separate single chain and double chain DNA, Produce with  5′- Decomposition products at the end of phosphoric acid . Under normal conditions, the decomposition products contain 1 To 8—12 Oligonucleotides , The average size is equal to four nucleotides . At the beginning of the reaction, it seems to decompose first dpPupPy key , However, the existence of divalent ions has a significant effect on the mode of cutoff . Therefore, the enzyme is easy to crystallize , So in nucleic acid   It is widely used in the research of ; And because the whole structure has been made clear , So it is also the material of enzyme chemistry .

AI Meijie Worthington Deoxyribonuclease I Specificity ：

bpDNase I  Not base or sequence specific ; however , It does not cut randomly . It shows priority in pyrimidine  5'  Side cracking , And especially in alternative copolymers （Bernardi  wait forsomeone  1975  and  Lomonossoff  wait forsomeone  1981）. It has been shown that , The change of twist angle is  DNase I  distinguish （Dickerson  and  Drew 1981）.DNase I  The specificity also depends on the presence of divalent cations . In existence  Ca2+  and  Mg2+  Under the circumstances , It can cause single chain breaks , But in being  Mn2+  It will cause double chain breakage （Junowicz  and  Spencer 1973, as well as  Campbell  and  Jackson 1980）.

AI Meijie Worthington Deoxyribonuclease I Molecular characteristics ：

And human 、 Mice are similar to rats , Bovine pancreas  DNase I  Genes are made up of  9  Composed of exons , Only the last  8  Exons encode the protein （De María  and  Arruti 2003）. The nascent protein is encoded by exon 2  22  Amino acid signal sequences are directed to secretory pathway organelles . Main active site residues  H166  By exons  6  code （De María  and  Arruti 2003  and  Kraehenbuhl  wait forsomeone  1977）. Although the exons of cattle and other mammals are almost the same length , But the length of introns varies greatly .TATA  Box sequence in exon  I  The upstream  35 bp（De María  and  Arruti 2003）. It has been suggested that the multiple splicing events that affect the coding sequence may be down-regulation  DNase I  The mechanism of expression （Liu  wait forsomeone  1997）.

Deoxyribonuclease I Related research ：

Actin

Albumin , Nuclease free

Deoxyribonuclease  II

Deoxyribonucleic acid and related products

Histone

Lysozyme

Nuclease , Micrococcus

Nuclease ,S1

Phosphatase , alkalinity

Phosphodiesterase  I

Phosphodiesterase  II

protease K

Reverse transcriptase , restructuring  HIV

Ribonuclease A

Ribonuclease  T1

Ribonuclease ,E-Rase RNase  Mixture

RNA