Plays a crucial role in the peroxisomal oxidation of branched-chain fatty acids. Catalyzes the last step of the peroxisomal beta-oxidation of branched chain fatty acids and the side chain of the bile acid intermediates di- and trihydroxycoprostanic acids (DHCA and THCA) (By similarity). Also active with medium and long straight chain 3-oxoacyl-CoAs. Stimulates the microsomal conversion of 7-dehydrocholesterol to cholesterol and transfers phosphatidylcholine and 7-dehydrocholesterol between membrances, in vitro (By similarity). Isoforms SCP2 and SCPx cooperate in peroxisomal oxidation of certain naturally occurring tetramethyl-branched fatty acyl-CoAs (By similarity). Mediates the transfer of all common phospholipids, cholesterol and gangliosides from the endoplasmic reticulum to the plasma membrane. May play a role in regulating steroidogenesis (By similarity). Stimulates the microsomal conversion of 7-dehydrocholesterol to cholesterol (By similarity). Also binds fatty acids and fatty acyl Coenzyme A (CoA) such as phytanoyl-CoA. Involved in the regulation phospholipid synthesis in endoplasmic reticulum enhancing the incorporation of exogenous fatty acid into glycerides. Seems to stimulate the rate-limiting step in phosphatidic acid formation mediated by GPAT3. Isoforms SCP2 and SCPx cooperate in peroxisomal oxidation of certain naturally occurring tetramethyl-branched fatty acyl-CoAs (By similarity). choloyl-CoA + propanoyl-CoA = 3alpha,7alpha,12alpha-trihydroxy-24-oxo-5beta-cholestan-26-oyl-CoA + CoA acetyl-CoA + an acyl-CoA = a 3-oxoacyl-CoA + CoA acetyl-CoA + hexanoyl-CoA = 3-oxooctanoyl-CoA + CoA acetyl-CoA + tetradecanoyl-CoA = 3-oxohexadecanoyl-CoA + CoA 3-oxohexadecanedioyl-CoA + CoA = acetyl-CoA + tetradecanedioyl-CoA propanoyl-CoA + tetradecanoyl-CoA = 3-oxo-2-methylhexadecanoyl-CoA + CoA acetyl-CoA + butanoyl-CoA = 3-oxohexanoyl-CoA + CoA acetyl-CoA + octanoyl-CoA = 3-oxodecanoyl-CoA + CoA acetyl-CoA + decanoyl-CoA = 3-oxododecanoyl-CoA + CoA acetyl-CoA + dodecanoyl-CoA = 3-oxotetradecanoyl-CoA + CoA acetyl-CoA + hexadecanoyl-CoA = 3-oxooctadecanoyl-CoA + CoA 3-oxo-(9Z-octadecenoyl)-CoA + CoA = (7Z)-hexadecenoyl-CoA + acetyl-CoA 7-dehydrocholesterol(in) = 7-dehydrocholesterol(out) 7-dehydrocholesterol(in) = 7-dehydrocholesterol(out) 4,8,12-trimethyltridecanoyl-CoA + propanoyl-CoA = 3-oxopristanoyl-CoA + CoA Interacts with PEX5; the interaction is essential for peroxisomal import. preSCP2, a protein with a molecular mass of about 15 kDa, is processed into its mature form (SCP2) by proteolytic cleavage of a 20 residue leader sequence after translocation into peroxisomes. Contains a putative mitochondrial transit peptide at positions 1-20.