Salvage enzyme
Encyclopedia
Salvage enzymes are enzymes, nucleoside
kinases, required during cell division
to "salvage" nucleotides, present in body fluids, for the manufacture of DNA.They catalyze the phosphorylation of nucleosides to nucleoside - 5'-phosphates, that are further phosphorylated to triphosphates, that can be built into the growing DNA chain. The salvage enzymes are synthesized during the G1 phase
in anticipation of DNA synthesis
. After the cell division
has been completed, the salvage enzymes, no longer required, are degraded. During interphase
the cell derives its requirement of nucleoside-5'-phosphates by de novo synthesis
, that leads directly to the 5'-monophosphate nucleotides.
Nucleoside
Nucleosides are glycosylamines consisting of a nucleobase bound to a ribose or deoxyribose sugar via a beta-glycosidic linkage...
kinases, required during cell division
Cell division
Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...
to "salvage" nucleotides, present in body fluids, for the manufacture of DNA.They catalyze the phosphorylation of nucleosides to nucleoside - 5'-phosphates, that are further phosphorylated to triphosphates, that can be built into the growing DNA chain. The salvage enzymes are synthesized during the G1 phase
Cell cycle
The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...
in anticipation of DNA synthesis
DNA replication
DNA replication is a biological process that occurs in all living organisms and copies their DNA; it is the basis for biological inheritance. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule...
. After the cell division
Cell division
Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...
has been completed, the salvage enzymes, no longer required, are degraded. During interphase
Cell cycle
The cell cycle, or cell-division cycle, is the series of events that takes place in a cell leading to its division and duplication . In cells without a nucleus , the cell cycle occurs via a process termed binary fission...
the cell derives its requirement of nucleoside-5'-phosphates by de novo synthesis
De novo synthesis
De novo synthesis refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to their being recycled after partial degradation. For example, nucleotides are not needed in the diet as they can be constructed from small precursor molecules such as...
, that leads directly to the 5'-monophosphate nucleotides.