Nitric Oxide Synthase: Difference between revisions

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==== Substrate binding ====

The active site is highly conserved in the different NOS species. Thus it is possible to discuss substrate binding i general terms. The NOS enzyme binds its substrate (L-argignine) in the distal pocket by hydrogen bindings both to the guanidino[http://en.wikipedia.org/wiki/Guanidino] end and the amino acid end. <scene name='Nitric_oxide_synthase/Substratebinding_test/1'>Substrate in the catalytic site</scene> is shown in green with the heme and H4B shown. NOS binds its substrate by coordinating CO(or O2) to the heme at the site occupied by oxygen<ref>PMID:9376373 </ref>(it is the opposite site of the Cys coordination to heme - look in the 'heme' section). The binding of substrate leads to a 2-step transformation first to N-hydroxy-L-arginine (the tightly bound intermideate) and then NO and L-Citrulline. The product NO can then either diffuse out of the <scene name='Nitric_oxide_synthase/Substratebinding_distal_pocket/1'>~~distal pocket~~</scene> or bind to the heme and function in NO auto-inhibition though this inhibition is diverse throughout the 3 isoforms<ref>PMID:15598509</ref>.

The active site is highly conserved in the different NOS species. Thus it is possible to discuss substrate binding i general terms. The NOS enzyme binds its substrate (L-argignine) in the distal pocket by hydrogen bindings both to the guanidino[http://en.wikipedia.org/wiki/Guanidino] end and the amino acid end. <scene name='Nitric_oxide_synthase/Substratebinding_test/1'>Substrate in the catalytic site</scene> is shown in green with the heme and H4B shown. NOS binds its substrate by coordinating CO(or O2) to the heme at the site occupied by oxygen<ref>PMID:9376373 </ref>(it is the opposite site of the Cys coordination to heme - look in the 'heme' section). The binding of substrate leads to a 2-step transformation first to N-hydroxy-L-arginine (the tightly bound intermideate) and then NO and L-Citrulline. The product NO can then either diffuse out of the <scene name='Nitric_oxide_synthase/Substratebinding_distal_pocket/1'>cavity</scene> or bind to the heme and function in NO auto-inhibition though this inhibition is diverse throughout the 3 isoforms<ref>PMID:15598509</ref>.

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Nitric Oxide Synthase: Difference between revisions

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 ==== Substrate binding ====
-The active site is highly conserved in the different NOS species. Thus it is possible to discuss substrate binding i general terms. The NOS enzyme binds its substrate (L-argignine) in the distal pocket by hydrogen bindings both to the guanidino[http://en.wikipedia.org/wiki/Guanidino] end and the amino acid end. <scene name='Nitric_oxide_synthase/Substratebinding_test/1'>Substrate in the catalytic site</scene> is shown in green with the heme and H<sub>4</sub>B shown. NOS binds its substrate by coordinating CO(or O<sub>2</sub>) to the heme at the site occupied by oxygen<ref>PMID:9376373 </ref>(it is the opposite site of the Cys coordination to heme - look in the 'heme' section). The binding of substrate leads to a 2-step transformation first to N-hydroxy-L-arginine (the tightly bound intermideate) and then NO and L-Citrulline. The product NO can then either diffuse out of the <scene name='Nitric_oxide_synthase/Substratebinding_distal_pocket/1'>distal pocket</scene> or bind to the heme and function in NO auto-inhibition though this inhibition is diverse throughout the 3 isoforms<ref>PMID:15598509</ref>.
+The active site is highly conserved in the different NOS species. Thus it is possible to discuss substrate binding i general terms. The NOS enzyme binds its substrate (L-argignine) in the distal pocket by hydrogen bindings both to the guanidino[http://en.wikipedia.org/wiki/Guanidino] end and the amino acid end. <scene name='Nitric_oxide_synthase/Substratebinding_test/1'>Substrate in the catalytic site</scene> is shown in green with the heme and H<sub>4</sub>B shown. NOS binds its substrate by coordinating CO(or O<sub>2</sub>) to the heme at the site occupied by oxygen<ref>PMID:9376373 </ref>(it is the opposite site of the Cys coordination to heme - look in the 'heme' section). The binding of substrate leads to a 2-step transformation first to N-hydroxy-L-arginine (the tightly bound intermideate) and then NO and L-Citrulline. The product NO can then either diffuse out of the <scene name='Nitric_oxide_synthase/Substratebinding_distal_pocket/1'>cavity</scene> or bind to the heme and function in NO auto-inhibition though this inhibition is diverse throughout the 3 isoforms<ref>PMID:15598509</ref>.
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