MAN1B1（mannosidase alpha class 1B member 1），癌症关联基因，基因ID：11253，这个基因编码一种属于糖基水解酶47家族的酶。该酶在N-聚糖生物合成中发挥作用，是一种I类α-1，2-甘露糖苷酶，专门将man9glcnac转化为man8glcnac异构体b。在内质网相关降解途径中，需要将N-聚糖修饰为man5-6glcnac2。该基因突变导致常染色体隐性智力残疾。选择性剪接导致多个转录变体。在11号染色体上发现了一个相关的假基因。[由RefSeq提供，2011年12月]This gene encodes an enzyme belonging to the glycosyl hydrolase 47 family. This enzyme functions in N-glycan biosynthesis， and is a class I alpha-1，2-mannosidase that specifically converts Man9GlcNAc to Man8GlcNAc isomer B. It is required for N-glycan trimming to Man5-6GlcNAc2 in the endoplasmic-reticulum-associated degradation pathway. Mutations in this gene cause autosomal-recessive intellectual disability. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 11. [provided by RefSeq， Dec 2011]。