Any small globular plasma protein. α1-Microglobulin is a plasma protein (184 aa), one of the lipocalin superfamily, the product of a gene that encodes a precursor (352 aa) which is proteolytically cleaved into α1-microglobulin and bikunin. Present in free form and in a complex with IgA; involved in regulation of the inflammatory process. β2-Microglobulin (b2M) is an immunoglobulin-like serum protein (119 aa) that is also the β chain of MHC class I molecules (histocompatibility antigens). Defects in b2M cause hypercatabolic hypoproteinaemia in which there is marked reduction in serum concentrations of immunoglobulin and albumin because of abnormal rates of degradation.
Subjects: Medicine and Health.