Bovine conglutinin is a collagen-like protein.
Bovine conglutinin is a collagen-like protein.
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牛凝集素是一种类胶原蛋白。
作者：
A. Davis;P. Lachmann
刀豆球蛋白是一种牛血浆蛋白，其相对较大且不对称，具有升高的甘氨酸含量和一定程度的脯氨酸含量。虽然其生理功能是未知的，但已知的是，在钙的存在下，结合到酵母细胞壁和固相灭活的补体的第三组分。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳还原条件下，分离的conglutinin似乎由一个单一的多肽链（Mr 48 000）。未还原的连接蛋白由表观分子量约为300 000的单一染色条带组成。戊二醛和二甲基辛二酰亚胺的交联实验表明，这个先生300 000分子由六个二硫键连接的多肽链。氨基酸组成显示羟赖氨酸和羟脯氨酸以及升高的甘氨酸和脯氨酸含量。用细菌胶原酶消化还原的、烷基化的胶原蛋白导致形成沉淀物，该沉淀物由Mr 24 000肽组成，该肽用大量胶原酶消化至Mr 21 000。这些肽含有较少的甘氨酸，脯氨酸，羟赖氨酸，羟脯氨酸比完整的蛋白质。然而，来自该消化混合物的上清液富含这四种氨基酸，其中甘氨酸占总量的近三分之一。用胃蛋白酶在37 ° C下长时间消化导致富含甘氨酸、脯氨酸、羟脯氨酸和羟赖氨酸的Mr 20 000肽。氨基末端序列分析表明，甘氨酸-X-Y重复序列开始于残基26。（250字处删节）
Conglutinin is a bovine plasma protein which is relatively large and asymmetric with elevated contents of glycine and, to some extent, proline. Although its physiologic function is unknown, conglutinin is known to bind, in the presence of calcium, to yeast cell walls and to the solid-phase-inactivated third component of complement. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, isolated conglutinin appeared to consist of a single polypeptide chain (Mr 48 000). Unreduced conglutinin consisted of a single stained band with an apparent molecular weight of approximately 300 000. Cross-linking experiments with glutaraldehyde and dimethyl suberimidate suggested that this Mr 300 000 molecule consists of six of the disulfide-linked polypeptide chains. Amino acid composition revealed hydroxylysine and hydroxyproline together with elevated glycine and proline contents. Digestion of reduced, alkylated conglutinin with bacterial collagenase resulted in formation of a precipitate which consisted of an Mr 24 000 peptide which was digested to Mr 21 000 with large quantities of collagenase. These peptides contained less glycine, proline, hydroxylysine, and hydroxyproline than did the intact protein. The supernatant from this digestion mixture was, however, enriched in these four amino acids, with glycine making up nearly one-third of the total. Prolonged digestion with pepsin at 37 degrees C resulted in an Mr 20 000 peptide which was enriched in glycine, proline, hydroxyproline, and hydroxylysine. Amino-terminal sequence analysis showed that the glycine-X-Y repeating sequence begins at residue 26.(ABSTRACT TRUNCATED AT 250 WORDS)