Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AlbertaT6G 2P5, Canada.
J Dairy Res. 2020 Feb;87(1):127-133. doi: 10.1017/S0022029919000918. Epub 2020 Feb 3.
Bovine κ-casein glycomacropeptide (GMP) found in cheese whey is a sialylated phosphorylated peptide which is thought to be a potential ingredient for functional food as well as dietetic food. This study was undertaken to determine whether high purity GMP can be isolated from soluble whey fraction (SWF) using column chromatography on food grade anion exchange resin and chitin as an adsorbent. Samples of commercially available anion exchange resin (resin A, resin B and resin C) and those of chitin (chitin A, chitin B and chitin C) were examined in this experiment. The GMP fraction obtained from each column was analyzed for amino acid composition which reflects the purity of the peptide. Major findings for commercial anion exchange resin were that: (1) the proportion of GMP monitored as sialic acid in total recovered sialic acid was similar among the three samples of resin accounting for average 78% of recovered sialic acid; (2) the GMP fraction from resin A or resin B contained undetectable level of contaminating amino acids including phenylalanine, histidine, arginine and tyrosine; (3) the GMP fraction from resin C contained small amounts (<1 mol%) of contaminating amino acids, arginine, phenylalanine and tyrosine; and (4) the GMP binding capacity expressed as mg/100 mg dry weight of resin was more than 2.5 times higher in resin C (average 22.9) than in resin A or resin B with no difference between resin A and resin B averaging 8.7. Results obtained for chitin A, chitin B and chitin C were in general similar to those found with resin A and resin B. Since chitin has a remarkable GMP binding capacity averaging 8.6 mg/100 mg dry weight of chitin, it may be a useful adsorbent for whey fractionation. Further research is needed to develop an efficient inexpensive method to purify GMP.
乳κ-酪蛋白糖巨肽（GMP）存在于奶酪乳清中，是一种唾液酸化的磷酸化肽，被认为是功能性食品和饮食食品的潜在成分。本研究旨在确定是否可以使用食品级阴离子交换树脂和几丁质作为吸附剂从可溶性乳清部分（SWF）中分离出高纯度 GMP。本实验研究了市售阴离子交换树脂（树脂 A、树脂 B 和树脂 C）和几丁质（几丁质 A、几丁质 B 和几丁质 C）的样品。从每个柱子获得的 GMP 部分被分析氨基酸组成，这反映了肽的纯度。商业阴离子交换树脂的主要发现是：（1）作为总回收唾液酸中唾液酸监测的 GMP 比例在三种树脂样本中相似，占回收唾液酸的平均 78%；（2）树脂 A 或树脂 B 的 GMP 部分不含可检测到的杂质氨基酸，包括苯丙氨酸、组氨酸、精氨酸和酪氨酸；（3）树脂 C 的 GMP 部分含有少量（<1mol%）杂质氨基酸，包括精氨酸、苯丙氨酸和酪氨酸；（4）以树脂干重 100mg 表示的 GMP 结合能力在树脂 C 中（平均 22.9）比树脂 A 或树脂 B 高 2.5 倍以上，树脂 A 和树脂 B 之间没有差异，平均为 8.7。几丁质 A、几丁质 B 和几丁质 C 的结果与树脂 A 和树脂 B 的结果大致相似。由于几丁质具有 8.6mg/100mg 干重几丁质的显著 GMP 结合能力，因此它可能是乳清分级的有用吸附剂。需要进一步研究以开发一种高效、廉价的 GMP 纯化方法。
