蛋白酶体是一种多催化蛋白酶复合物，具有高度有序的环状20S核结构。核心结构由4个28个不相同亚单位的环组成，2个环由7个α亚单位组成，2个环由7个β亚单位组成。蛋白酶体以高浓度分布于真核细胞，并在非溶酶体途径的ATP/泛素依赖过程中分裂肽。经修饰的蛋白酶体免疫蛋白酶体的一个基本功能是加工I类mhc肽。这个基因编码蛋白酶体B型家族的一个成员，也被称为t1b家族，是一个20s核心β亚单位。该基因位于MHC（主要组织相容性复合体）的Ⅱ类区域。该基因的表达由γ干扰素诱导，该基因产物取代了免疫蛋白酶体中的催化亚单位3（蛋白酶体β5亚单位）。蛋白水解过程需要产生一个成熟的亚单位。已经鉴定出两种编码两种亚型的选择性转录物；两种亚型都经过处理以产生相同的成熟亚基。
The proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. The core structure is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. This gene encodes a member of the proteasome B-type family, also known as the T1B family, that is a 20S core beta subunit. This gene is located in the class II region of the MHC (major histocompatibility complex). Expression of this gene is induced by gamma interferon and this gene product replaces catalytic subunit 3 (proteasome beta 5 subunit) in the immunoproteasome. Proteolytic processing is required to generate a mature subunit. Two alternative transcripts encoding two isoforms have been identified; both isoforms are processed to yield the same mature subunit.