preferred_name: an N-(1,2 saturated very-long-chain fatty acyl)-(R)-4-hydroxysphingoid base + 2 Fe(II)-[cytochrome b5] + O2 + 2 H(+) => an N-(2R-hydroxy-very-long-chain fatty acyl)-(R)-4-hydroxysphingoid base + 2 Fe(III)-[cytochrome b5] + H2O