The B1-immunoreactive proteins of the perinatal submandibular gland: similarity to the major parotid gland protein, RPSP.
The B1-immunoreactive proteins of type III cells of the perinatal rat submandibular gland are immunologically cross-reactive with proteins of both the sublingual and parotid glands; in particular, protein SMG-A appears similar to a major parotid protein. We isolated SMG-A and the parotid protein (known as M1 or leucine-rich protein), prepared polyclonal antibodies to them, and compared their biochemical properties and immunological reactivities. They were identical in their molecular weight on SDS-PAGE (23.5 kDa), tenacious binding to Affi-gel Blue, isoelectric point (pH 4.53), and proteolysis to a 14 kDa peptide: Antibodies to SMG-A showed reactivity with protein SMG-C, a product of the neonatal type I cells, as well as with proteins SMG-B1 and SMG-B2, contrasted with the absence of reactivity of anti-M1 IgG with these proteins. Anti-M1 reacted with the "parotid secretory protein" (PSP) of the mouse, and M1 appears to be the homologue, in the rat, of mouse PSP.
Ball
W D
WD
Department of Anatomy, Howard University College of Medicine, Washington, DC 20059.
Hand
A R
AR
Moreira
J E
JE
Iversen
J M
JM
Robinovitch
M R
MR
D000818:Animals; D000831:Animals, Newborn; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010306:Parotid Gland / Q000737:chemistry / Q000648:ultrastructure; D011817:Rabbits; D051381:Rats; D012471:Salivary Proteins and Peptides / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D012967:Sodium Dodecyl Sulfate; D013045:Species Specificity; D013361:Sublingual Gland / Q000737:chemistry / Q000648:ultrastructure; D013363:Submandibular Gland / Q000737:chemistry* / Q000254:growth & development / Q000648:ultrastructure
C511597:Bpifa2 protein, mouse; C511598:Bpifa2 protein, rat; D012471:Salivary Proteins and Peptides; C072564:Smgb Protein, rat; D012967:Sodium Dodecyl Sulfate; D010450:Endopeptidases