|
Enter a Search String | | Special character and space not allowed in the query term.
Search string should be at least 2 characters long. |
Molecule Parameter List for Heme | The statistics table lists the distribution of a molecule acting either as a substrate, product, enzyme or as a molecule within the network.
The text color of a molecule is highlighted by  color. | | Statistics |
| Heme participated as | Molecule | Sum total of | Enzyme | Substrate of an enzyme | Product of an enzyme | Substrate in Reaction | Product in Reaction | | No. of occurrences | 1 | 0 | 0 | 1 | 0 | 0 | 0 |
Accession and Pathway Details | |
| Accession Name | Accession No. | Accession Type | Pathway Link | CO_activation_
of_GC | 28 | Pathway |
sGC | Carbon Monoxide is an activator of soluble Guanylyl Cyclase and has been implicated as a neuronal messenger [Ingi T. et al. Neuron (1996) 16(4):835-42].
CO binds to the heme group on sGC, similar to NO binding. Exogenous CO at similar conc. to endogenous levels were used to study the extent of activation of GC. Olfactory receptor neurons were used by Ingi et al., to investigate the relationship of CO to cGMP levels, as these cells have high levels of HO activity but no NOS activity.
Kharitonov VG. et al. Proc Natl Acad Sci U S A. (1995) 92(7):2568-71 and
Kharitonov VG. et al. Biochemistry (1999) 38(33):10699-706 report the presence of a six coordinate and a five coordinate intermediate of carboxy GC, induced by CO. Considering that activation of sGC by CO is similar in almost all tissues, some rates have been taken from original published works cited as references in Kharitonov et al., and Ingi et al., the primary datasources, this model is based on. |
Heme acting as a Molecule in CO_activation_of_GC Network
| Name | Accession Name | Pathway Name | Initial Conc.
(uM) | Volume
(fL) | Buffered | | Heme | CO_activation_
of_GC
Accession No. : 28 | sGC
Pathway No. : 140 | 11.3 | 0.0016667 | No | | Total cellular heme determined spectrophotometrically to be 1.5 nmol/mg protein. (Ingi et al., 1996, Neuron,16:835-842), a value resembling reported heme content in neuronal tissues. Ingi et al., also reports in J Neurosci. 1996,16(18):5621-5628, that Brain has significant levels of heme (1.3 nmol/mg protein) Conc calculated/used 21.3 |
Heme acting as a Substrate for an Enzyme in CO_activation_of_GC Network
Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | Hemeoxyg2 /
HOXY | CO_activation_
of_GC
Accession No. : 28 | sGC
Pathway No. : 140 | 3.80004 | 0.3556 | 4 | explicit E-S complex | Substrate
Heme
Product
CO
| | Ingi et al., J Neurosci., 1996, 16(18):5621-5628, report the production rates of heme precursors and metabolites. The rate reported for CO from heme is 2.9 pmol/mg protein over 6 hr. Their results indicate high HO activity in brain (along with significant levels of heme) at around 280pmol of bilirubin/mg/min. Montellano PRO, Curr. Opin. in Chem. Biol, 2000,4:221-227 and refs cited in his paper were also studied initially. Km for free heme is around 3.8 +/- 0.5 uM.(Bonkovsky et al., 1990, 189(1):155-166) |
| Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
This Copyright is applied to ensure that the contents of this database remain freely available. Please see FAQ for details. |
|
