C1a

C1A is an alphanumeric designation that appears in multiple domains to label models, variants, or groups. Notable uses include aviation and biochemistry.

In aviation, the C-1A Trader is a United States Navy carrier onboard delivery aircraft developed from the Grumman Gulfstream I airframe. It served as a compact transport for personnel, mail, and cargo between ships and shore facilities, primarily from the 1960s into the late 20th century.

In biochemistry, C1A denotes the papain-like cysteine protease family within the MEROPS enzyme classification system. Family C1A includes enzymes such as papain and several mammalian cathepsins (e.g., B, L, S). These enzymes hydrolyze peptide bonds using a catalytic cysteine and histidine, and function in protein degradation within lysosomes as well as in extracellular remodeling. The family is widespread across eukaryotes.

Other uses of the C1A designation occur in technical catalogs, gene symbols, or product SKUs, depending on the context. Because it is a general alphanumeric code, its exact meaning is domain-specific and requires contextual information to determine which C1A is being referred to.