proton-dependent oligopeptide secondary active transmembrane transporter activity

Definition

Target type: molecularfunction

Enables the transfer of a oligopeptide from one side of a membrane to the other, up its concentration gradient. The transporter binds the solute and undergoes a series of conformational changes. Transport works equally well in either direction and is driven by proton movement. [GOC:mtg_transport, OMIM:600544]

Proton-dependent oligopeptide secondary active transmembrane transporter activity involves the movement of oligopeptides across cell membranes using the electrochemical gradient of protons (H+) as the driving force. These transporters are integral membrane proteins that typically possess multiple transmembrane domains. They function by coupling the downhill movement of protons down their concentration gradient to the uphill movement of oligopeptides against their concentration gradient. This process is known as secondary active transport, as it indirectly utilizes energy stored in the proton gradient, which is established by primary active transport mechanisms such as ATPases.

The mechanism of transport involves the following steps:

1. **Binding of protons:** The transporter binds protons on one side of the membrane, typically the extracellular side. This binding event causes a conformational change in the transporter protein.
2. **Oligopeptide binding:** The conformational change facilitates the binding of oligopeptides on the same side of the membrane as the protons.
3. **Translocation:** The transporter undergoes another conformational change, moving the bound oligopeptides across the membrane to the opposite side.
4. **Proton release:** The transporter releases protons on the other side of the membrane, typically the intracellular side. This release restores the original conformation of the transporter, ready for another cycle.

The specificity of these transporters for oligopeptides varies depending on the transporter. Some transporters are highly specific for certain types of oligopeptides, while others exhibit broader substrate specificity.

These transporters play crucial roles in various physiological processes, including:

* **Nutrient uptake:** Transporting essential amino acids and peptides into cells.
* **Drug transport:** Mediating the uptake and efflux of various drugs.
* **Immune function:** Facilitating the transport of peptides involved in antigen presentation.
* **Cellular signaling:** Regulating the intracellular concentrations of signaling peptides.

Mutations or dysregulation of these transporters can lead to various diseases, including:

* **Malabsorption disorders:** Impaired nutrient absorption due to defects in peptide transport.
* **Drug resistance:** Altered drug uptake and efflux due to changes in transporter activity.
* **Immune dysfunction:** Compromised antigen presentation and immune responses.

In summary, proton-dependent oligopeptide secondary active transmembrane transporter activity is a vital process that plays a crucial role in various cellular functions, contributing to nutrient uptake, drug transport, immune responses, and cellular signaling.'
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Proteins (1)

Compounds (118)