|Protein Name||6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3|
|Ref Sequence ID||NP_001071305.1|
|Protein Existence Status||Unreviewed: Experimental evidence at transcript level|
|Protein Function||synthesis and degradatioil of fructose 2,6-bisphosphate (Fru-2,6-P2), which is an important regulator of glycolysis; atleast 3 isoforms in mammals - the liver (L), muscle (M) and heart (H) type isoenzymes .|
|Biochemical Properties||The three isoenzymes exist as homodimers; PFK/FBPase ratio is different for all 3 isozymes - 0.1-0.2 for type M and 80 for type H;Types L and H are substrates of the cyclic AMP-dependent; PKA treatment had no effect on vmax of PFK-2, its Km for MgATP, or its sensitivity towards inhibition by citrate; PKA treatment caused increased activity of PFK 2 at pH 7.0-7.5; Bovine heart FBPase-2 activity was maximal at pH 6.0; Treatment with PKA caused a small but insignificant increase in FBPase-2 activity measured at pH 5.5 and 6|
|Significance in milk||Involved in glucose metabolism; upregulated in early lactation period as compared to late pregnanacy|
|PTMs||phosphoryalted - phosphorylated in the presence of MgATP and cyclic AMP-dependent protein kinasc (PKA) or protein kinasc C (PKC); In rat liver PFK-YFBPase-2,phosphorylation site for PKA lies in the N-terminal domain at Ser-32, for bovine heart PFK-2/FBPase-2 the phosphorylation sites for PKA and PKC are in the C-terminal domain at Ser-466 and Thr-47S, respectively|
| Site(s) of PTM(s) |
|Significance of PTMs||phosphorylation of the liver type leads to PFK-2 inactivation whereas phosphorylation of the Heart-type results in a small activation of PFK-2; Heart-Type PFK-2/FBPase-2 is also a substrate of protein kinase C (PKC), but phosphorylation has no effect on its enzyme activities|
|Bibliography||1. Rider, M. H., van Damme, J., Vertommen, D., Michel, A., Vandekerckhove, J., & Hue, L. (1992). Evidence for new phosphorylation sites for protein kinase C and cyclic AMP-dependent protein kinase in bovine heart 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. FEBS Letters, 310(2), 139–142. https://doi.org/10.1016/0014-5793(92)81315-d. |
2. Jiang, L., Sørensen, P., Røntved, C., Vels, L., & Ingvartsen, K. L. (2008). Gene expression profiling of liver from dairy cows treated intra-mammary with lipopolysaccharide. BMC Genomics, 9. https://doi.org/10.1186/1471-2164-9-443.
3. Rider, M. H., Vandamme, J., Lebeau, E., Vertommen, D., Vidal, H., Rousseau, G. G., … Hue, L. (1992). The two forms of bovine heart 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase result from alternative splicing. The Biochemical Journal, 285 ( Pt 2), 405–411. https://doi.org/10.1042/bj2850405.
4. Finucane, K. A., McFadden, T. B., Bond, J. P., Kennelly, J. J., & Zhao, F.-Q. (2008). Onset of lactation in the bovine mammary gland: gene expression profiling indicates a strong inhibition of gene expression in cell proliferation. Functional & Integrative Genomics, 8(3), 251–264. https://doi.org/10.1007/s10142-008-0074-y.