Allows the energy independent passage of small (less than 1000 Da) solutes across a membrane. The transmembrane portions of porins consist exclusively of beta-strands which form a beta-barrel. They are found in the outer membranes of Gram-negative bacteria, mitochondria, plastids and possibly acid-fast Gram-positive bacteria.

The chemical reactions involving L-methylmalonyl-CoA, the levorotatory isomer of 2-carboxypropanoyl-CoA. S-methylmalonyl-CoA is an intermediate in the beta oxidation of odd-numbered fatty acids in animals.

The chemical reactions involving nicotinamide riboside, the product of the formation of a glycosidic bond between ribose and nicotinamide.

outward rectifier potassium channel activity

The chemical reactions involving nicotinamide nucleotides, any nucleotide that contains combined nicotinate (pyridine 3-carboxylic acid, or niacin).

ATP-activated inward rectifier potassium channel activity

The chemical reactions involving S-adenosylhomocysteine; the L-enantiomer is formed from S-adenosylmethionine and is a strong inhibitor of S-adenosylmethionine-mediated methylation reactions. It can be cleaved to form adenosine and homocysteine.

G-protein enhanced inward rectifier potassium channel activity

G-protein-enhanced inward rectifier potassium channel activity

stretch-activated, cation-selective, calcium channel activity

kainate selective glutamate receptor activity

Enables the directed movement of choline into, out of, within or between cells. Choline (2-hydroxyethyltrimethylammonium) is an amino alcohol that occurs widely in living organisms as a constituent of certain types of phospholipids and in the neurotransmitter acetylcholine.

Enables the directed movement of serotonin into, out of, within or between cells. Serotonin (5-hydroxytryptamine) is a monoamine neurotransmitter occurring in the peripheral and central nervous systems.

Enables the directed movement of biotin into, out of, within or between cells. Biotin is cis-tetrahydro-2-oxothieno(3,4-d)imidazoline-4-valeric acid; the (+) enantiomer is very widely distributed in cells and serves as a carrier in a number of enzymatic beta-carboxylation reactions.