Large peptides of bovine and guinea pig myelin basic proteins produced by limited peptic hydrolysis

Abstract

Bovine and guinea pig myelin basic proteins were cleaved with pepsin at pH 3.0 or pH 6.0 (enzyme/substrate, 1:500, w/w), and the peptides were isolated and identified. At pH 3.0 cleavage of the bovine protein occurred principally at three sites: Phe-Phe (88-89), Phe-Phe (42-43), and Leu-Asp (36-37). Minor cleavages occurred at Leu-Ser (110-111), Phe-Ser (113-114), and Ile-Phe (152-153). A study of the time course of the hydrolysis showed that the reaction was biphasic; nearly all of the protein was cleaved at Phe-Phe (88-89) before significant cleavages at other sites occurred. At pH 6.0 cleavage of the bovine protein occurred almost exclusively at a single site, the Phe-Phe bond at position 88-89, resulting in bisection of the protein. Treatment of the guinea pig protein with pepsin under the same conditions resulted in the production of peptides which were identical with those of the bovine protein in chromatographic and electrophoretic properties and in N-terminal and C-terminal residues but which differed slightly in amino acid composition.

Species Restriction of a Monoclonal Antibody Reacting with Residues 130 to 137 in Encephalitogenic Myelin Basic Protein

“…Peptide fragments of BP from monkeys, guinea pigs, and rabbits were prepared by limited peptic digestion and molecular sieve or ion-ex-SCIENCE, VOL. 214, 2 OCTOBER 1981 change chromatography (4). These were identified as monkey residues 1 to 90, 91 to 172, and 118 to 172; guinea pig residues 38 to 120 and 121 to 172; and rabbit residues 1 to 155 and 156 to 172 (3).…”

“…Two of these can be definitely eliminated, since the weakly reactive rabbit BP has the same sequence as the strongly reactive bovine BP at residues 119 to 124 and differs from bovine BP in residues 142 to 150 only at the one site (residue 145), where it is the same as the strongly reactive rat-L BP. The sequence 153 to 160 can probably be eliminated since the nonreactive guinea pig BP is probably the same as the strongly reactive bovine BP (4,10). There remains, therefore, only one region, residues 130 to 137, where all of the strongly reactive BP's are identical, where the weakly reactive rabbit BP has a single substitution at residue 133, and where two of the three nonreactive BP's are reported to have two or more substitutions at residues 130 to 131, 133 to 134, and 137.…”

“…The subjects were 20 right-handed normal control subjects and 58 patients at the Montreal Neurological Hospital who had undergone a unilateral excision of cortical tissue of the frontal (7 left, 14 right), temporal (13 left, 17 right), or paricto-occipital (4 left, 4 right) regions for the relief of epilepsy (4). When the temporal lobe was removed, the amygdala was partially or completely removed, and the hippocampus was partially removed.…”

Peptide bond specificity of calpain: Proteolysis of human myelin basic protein

“…Susceptibility of MBP to various proteinases has indicated a pivotal role for proteolytic enzymes in the pathophysiology of demyelination (Hashim, 1978;Benjamin and Smith, 1984;Banik, 1992). These proteinases include pepsin, trypsin, chymotrypsin, pronase (Hashim and Eylar, 1969;Martenson et al, 1975), neutral proteinases (Benjamin and Smith, 1984) and lysosomal enzymes cathepsins B and D (Marks et al, 1974;Benuck et al, 1975;Brostoff et al, 1974; and others; see reviews by Hashim 1978;Brostoff 1984). MBP has been shown to be readily digested by pepsin, trypsin, chymotrypsin, and pronase (Hashim and Eylar, 1969;Martenson et al, 1975).…”

Peptides of Myelin Basic Protein Are Encephalitogenic in Rats without the Aid of Emulsions

“…The antigens were MBP from Hartley guinea pig brain and its constituent peptides, the preparation and characterization of which have been reported previously (7)(8)(9)(10). For the first series of experiments, 11 nmol of MBP (0.2 mg) or peptides were dissolved in sterile saline and injected intraperitoneally always in a volume of 1 ml.…”